dacry- is a combining
form that refers to
tears or to tearing
(both words pronounced with a long
"e"), as in weeping.
The term is an almost direct borrowing of the Greek dakry, "a tear."
Thus, dacryadenitis is an inflammation ofthe lacrimal gland.
-dactyl- is a combining form referring to a
finger, or sometimes a toe, and is derived
from the Greek daktylos, "finger." Syndactyly (Greek syn, "together") is the condition
wherein adjacent digits are joined by a congenital web. Arachnodactyly is a term for
abnormally long, spindly fingers or toes, (see
arachnoid)
daltonism is a term for the sex-linked inherited
defect of red-green color blindness. It derives
from the name ofJohn Dalton (1766-1844), a
British physicist who wrote extensively on
color blindness, with which he himself was
afflicted.
dandruff is usually plainly evident as a condition; as a word, its origin is obscure. The first
syllable may relate to an archaic English dialect word for small scales of skin, hair, or
feathers. The second syllable probably comes
from the Old Norse hrufa, "scab." "Dander"
seems to be a contraction of "dandruff." In
any case, dandruff is probably the most frequent diagnosis evident by periodic physical
examination of healthy persons,
dartos is the name, as in tunica dartos, given
to a layer ofSmooth Muscle fibers intermingled with the fascia enveloping the testicles
in the scrotum. It is a borrowing of the Greek
word for "that which is flayed."
data is the plural (a point not always remembered by American speakers and writers) of
the Latin datum, “a thing given," the neuter
past participle of dare, "to give." In science,
data are assembled as facts, statistics, or the
like; one rarely encounters datum in reference to a single fact or statistic, but such use
would be entirely proper,
deadly (see mortal)
deaf in Middle English was spelled (and pronounced) "deef." So, the old-timer who pronounces the word to rhyme with "reef" is not
being comical; he is being archaic. The original Indo-European root likely was dheubh,
"dull to perception." Curiously, our adjective "absurd" bears a relation to deafness.
The Latin absurdus, "senseless or silly," is a
combination of ab-, "from," + surdus, "deaf,
unheeding."
debridement is a French word that combines
de, "not,” + brider, "to bridle,” thus literally
an "unbridling." Originally the term was
used for the process of cutting constrictive
bands but later, in surgery, came to refer to
the cutting away of injured or necrotic tissue.
deceased is a delicate way of saying "dead."
Not only is it delicate, itis used almostinvariably as a passive verb. No one with a civil
tongue speaks of "deceasing" himself or
anyone else. "Deceased" comes from the
Latin decedere, "to go away, to depart." This
is akin to referring to death as "a passing
away." Demise is a delicate noun for death.
Its origin is somewhat tortuous but probably
goes back to the Latin demittere, "to drop, to
send down." A worthy suggestion might be to
leave "deceased" and "demise" to persons
given to unctuous speech, such as morticians.
Dead, even though a four-letter word, is perfectly respectable.
deci- is a combining form subtracted from the
Latin decimus, "a tenth." The decimal system
is a numeration based on tenths. A deciliter
(abbreviated as "dL") is one-tenth of a liter,
or 100 milliliters. Incidentally, to decimate
means to subtract by one-tenth. In the
Roman army a harsh custom was to punish
mutiny by executing one of every ten men in
a rebellious unit. Uninformed writers or
speakers have been known to mistakenly use
"decimate" when they mean "annihilate",
i.e., "reduce to next to nothing."
decidua relates to the Latin verb decidere, "to
fall away." Deciduous trees are those from
which the leaves fall away in the chill of
autumn, and deciduous teeth are those shed
by youngsters in the normal course of development. In medicine, decidua is the name
given to the mucosa of the uterus that "falls
63
decoction dendrite
away" after parturition. The menstrual decidua is the hyperemic endometrium that is
shed in the normal menstrual cycle. A decision incidentally, is made after all other options or possibilities are discarded. The late
Chester Jones, long an esteemed clinician at
the Massachusetts General Hospital, is often
quoted as saying, "If you can't make a diagnosis, make a decision."
decoction (see concoction)
decrepit describes whatever is infirm or broken
down by age or hard use. The word is an
almost direct borrowing of the Latin decrepitus, "broken down," which, in turn, combines de-, "from," + crepare, "to make rattle
or creak."
decubitus is from the Latin verb decumbere, "to
lie down,” and is related to the Latin cubitum,
"the elbow." The Romans habitually rested
on their elbows when reclining. Decubitus is
a reclining position, usually further specified
as, for example, "the left lateral decubitus."
A decubitus ulcer is a bedsore, the consequence of pressure necrosis in a dependent
part from lying in one position too long.
Some related words are cubicle, a small
chamber in which to lie down; cubbyhole, a
small place to lay anything; incumbent, a
state of lying in or occupying; and concubine, one who lies with another,
decussation is from the Latin verb decussare,
"to divide crosswise," i.e., in the form of an
"X." The decussation of the anterior pyramids of the medulla oblongata is the crossing
of fibers from one side to the other so as to
form the lateral spinothalamic tracts,
defecate (see feces)
deferens (see vas)
degenerate comes from the Latin degenerare,
"to disgrace, to fall short of, or to be inferior
to one's ancestors." The derivation is from de-,
"down from," + genus, "the race.” In biology,
a degenerated cell is one that has deteriorated in structure or function when compared
with its normal counterparts ofthe "race."
deglutition is a combination of the de-,
"down," + the Latin glutire, "to gulp.” Now
the term is used in the gentlersense ofsimply
swallowing. A related word is glutton,
dehiscence can describe any abnormal gaping
or splitting of tissue but most often is applied
to separation of one or more layers of a partially healed wound or incision. The term is
taken from the Latin dehiscere, "to part,
divide, gape, or yawn."
dehydrate is a relatively recent hybrid term
contrived from the Latin de, "out of," + the
Greek hydor, "water." Whoever or whatever is
dehydrated has been deprived of water,
delirium is said to have been first used by
Aurelius Cornelius, better known as Celsus,
the celebrated Roman encyclopedist ofthe 1st
century A.D. The term is from the Latin de-,
"away from," + lira, "a furrow." Whoever is
mentally confused or incoherent cannot plow
a straight furrow and may be said to be out
of his groove.
deltoid refers to the shape of A (delta), the
fourth letter of the Greek alphabet. Hence, in
anatomy it can describe anything triangular
in configuration. The Deltoid (Muscle)(s) at the
shoulder is more or less triangular,
delusion comes from the Latin deludere, "to
dupe or deceive." The Latin ludere means "to
play or to amuse oneself," and a ludio was an
actor. One who suffers delusions is being
misled by imaginary circumstances,
dementia is the Latin word for "madness" and
comes from a combination of de-, "out of," +
mens, "the mind." Whoever is demented is
out of his mind. In a now outmoded classification, one form of mental derangement
often observed in younger persons was
known as dementia praecox, the second
word being Latin for "premature" (and the
source of our word "precocious"). Praecox
(prae-, "before," + coquere, "to cook") literally
means "uncooked" or "half-baked." Dementia praecox is now recognized as schizophrenia or one of its variants,
demise (see deceased)
demulcent comes from the Latin demulcere, "to
stroke lovingly or to caress," this being a combination of de-, "down," + mulcere, "to pet or
to soften." The Romans used demulcere particularly for the soothing stroking of horses.
In medicine, a demulcent is a soothing
preparation, especially one topically applied
to allay the irritation of inflamed surfaces,
dendrite means "branched like a tree" and is
derived from the Greek dendron, "tree." In
anatomy the term refers particularly to the
64
dengue dhobie itch
branching protoplasmic processes of nerve
cells. In botany, a rhododendron (Greek
rhodon, "rose") is an evergreen tree bearing
rose-colored flowers, and a philodendron
(Greek philos, “loving") is a climbing plant
with evergreen foliage and a propensity to
cling to trees.
dengue is the name of an acutely painful, febrile
illness endemic in the West Indies, the Middle
East, India, and the South Pacific. It is also
known as "breakbone fever." Its victims often
exhibit contortions because of intense muscle
and joint pains. One explanation is that the
name originated in the Swahili word ki-dinga,
"a sudden cramp or seizure." Another explanation relates to the Spanish denguero,
which means "affected or finicky." Slaves in
the West Indies were said to have called the
disease "dandy fever," presumably because
of the affected gait or postures of persons so
afflicted.
dental is taken from the Latin dens, "tooth or
tusk," and refers to whatever pertains to
teeth. The Latin densus means "hard, compact." Dentin is the principal substance of a
tooth, surrounding the pulp and being covered by enamel. Dentate means "arranged
like teeth"; the serrated mucocutaneous
border atthe anus is a dentate line.
deoxyribonucleic acid (see DNA)
depilatory refers to an agent, usually applied
as a cream, that removes unwanted hair. The
word is derived from the de-, "away," + the
Latin pilus, "hair."
depressor (see levator)
dermis comes from the Greek derma, "the skin."
A related Sanskrit word is dartis, "leather or
hide." When used alone, "dermis" refers to
the corium or dense layer of connective tissue
underneath the stratified squamous epithelium of the skin. As a combining form,
derm- contributes to a host ofterms pertaining to the skin, such as dermatology (the
science of the skin), dermatitis (inflammation of the skin), dermatome (an instrument for slicing the skin), dermatographia
(a condition wherein gentle stroking induces
a localized swelling that appears as a “writing" on the skin), and many others.
desiccate comes from the Latin desiccare, "to
dry up or to drain," this being derived from a
combination of de-, "away," + siccus, "dry."
The sicca complex (q.v.) is characterized by
excessive dryness ofthe normally moist membranes of the eye and mouth. The French sec,
"dry," particularly as it refers to wines lacking a sweet flavor, is a related word,
desmo- is a combining form taken from the
Greek desmos, "a band or fetter." Consequently, "desmo-" has come to refer to dense
fibrous or connective tissue. Desmoid describes a dense connective tissue neoplasm,
such as can occur in persons afflicted with
Gardner's syndrome. Desmoplasia (desmo-
- Greek plassein, "to form or mold") is a pervasive growth of fibrous tissue, particularly
thatinvesting certain neoplasms,
desquamation (see squamous)
detritus is the past participle of the Latin deterere, "to rub off or to rub away." Detritus,
then, is that which is rubbed away and refers,
as a medical term, to debris collected in or
around degenerating or necrotic tissue, (see
trituration)
detrusor comes from the Latin detrudere, "to
push down or to dislodge." The detrusor
muscle ofthe urinary bladderserves to aid in
the expulsion of urine.
dexter is the Latin word for "right," as opposed
to "left." As the combining form dextr-, it has
been incorporated in numerous anatomic
terms designating the right-sided component
of various bilaterally symmetric structures.
Because most people are naturally more facile
with their right hands, dexterity has come
to mean "skill or deftness." (see adroit)
dextrin is an intermediate product of the hydrolysis ofstarch and is so called because of
its dextrorotary ("turning to the right")
effect on polarized light,
dextrose is a colorless, crystalline hexose that
exhibits a dextrorotary property. More
specifically it is D-glucose, the "d" standing
for "dextro-." (see glucose)
dhobie itch is sometimes used as a nickname
for tinea cruris, a pruritic fungus infection
of the groin. Dhobie is the Hindustani word
for "a washerman." More specifically and
properly, "dhobie itch" refers to a contact dermatitis caused by hypersensitivity to the
marking fluid (bhilawanol oil) used by native
laundrymen in India.
65
dia- diastema
dia is a busy combining form taken from the
Greek preposition dia, which has many meanings, including "through, throughout, thoroughly, completely, across, and opposed to."
It appears as a prefix in many truly Greek
words and also has been used to lend a classical tone to many newly concocted words,
diabetes is a direct borrowing ofthe Greek word
for both a siphon and a compass, i.e., the
device used to draw circles. The Greek verb diabainein means to straddle or stand with legs
apart. The connection between a siphon and a
compass is simply that both instruments have
separated "legs.” Aretaeus the Cappadocian,
a famous Greek physician of the 2nd century
A.D., explained that diabetes as a disease was
so called because its victims "passed water
like a siphon." Polyuria has been long recognized as a cardinal symptom of diabetes. The
common sort of diabetic urine is laden with
sugar; hence the disease is diabetes mellitus, mellitus being Latin for "sweetened with
honey." The urine of patients with the rare
diabetes insipidus, on the other hand,
while voluminous, is lacking in sugar and
therefore tasteless or insipid (in-, "lacking," +
a derivative ofsapientia, "taste or sense"),
diagnosis is a direct borrowing of the Greek
diagnosis, butto the Greeks this meant specifically "a discrimination, a distinguishing, or
a discerning between two possibilities," in the
sense of resolving or deciding. The word combines dia- in any or almost all of its meanings
- gnosis, "knowledge", as applied to the discernment of a particular disease,
dialysis is a direct borrowing ofthe Greek word
for "a loosening of one thing from another." It
is almost exactly in that sense that "dialysis"
is used in medicine as "a process ofseparating
crystalloids or colloids in solution by the difference in their rates of diffusion through a
semipermeable membrane" (Dorland's).
diapedesis (d/a- + Greek pedan, “to leap") was
used by ancient writers to refer to eruption of
blood from wounds. In modern medical parlance, diapedesis refers to the escape of blood
corpuscles through the discontinuous endothelium of intact vessels, particularly as
this occurs in response to inflammation,
diaper refers not to the shape or purpose of the
familiar "three-comer pants" butto the fabric
and its color. The word combines dia-, "thoroughly," + the Greek aspros, "white." In ancient times the fabric was of fine texture and
pristinely white.
diaphoresis is a Greek word used by ancient
writers for "profuse sweating." It includes the
Greek phorein, "to convey." Diaphoresis is a
highfalutin way ofsaying "sweating."
diaphragm is a near borrowing of the Greek
diaphragma, "a partition," this being a combination of dia-, "across," + phragma, "a fence
or wall." Certain ancient writers ascribed
greatsignificance to the muscular diaphragm
separating the chest from the abdomen,
some even attributing to it powers of the
mind. This explains the naming of the
phrenic (Greek phren, "the mind") nerve that
supplies the diaphragm, possibly because the
diaphragm sits atop the spleen and kidneys,
organs once thought to be the seat of emotions. (see phrenic)
diaphysis incorporates the Greek physis,
"growth." Originally the term referred to "the
bursting of a bud" or "the point where a
branch grew from a stalk." Later, in
anatomy, "diaphysis" came to be applied to
the shaft of a long bone, particularly as a
growth center, in distinction to the epiphysis, a growth center atthe articular end of a
long bone.
diarrhea is an almost direct borrowing ofthe
Greek diarrhoia, "a flowing through," which
incorporates the Greek rhein, "to flow." The
ancients used the term, as we do, in reference
to excessive, watery evacuation from the
bowel.
diastase is a word coined in the 19th century as
the name for a substance (later identified as
an enzyme) capable of breaking down orseparating starch into its component sugars. It
was taken from the Greek diastasis, "a standing apart." Because diastase was thought of
as the prototype of an enzyme, the lastthree
letters, "-ase," came to be a suffix designating
an enzymatic property, (see -ase)
diastasis is still used in its original Greek
meaning when applied to a separation ofportions of bones or muscles normally attached.
diastema is a direct borrowing of the Greek
word that means "a standing apart." In biology, diastema refers to the zone of modified
66
diastole digitalis
protoplasm atthe equator of a cell that exists
previous to mitotic division ofthe cell. In dentistry, diastema is a gap between teeth that
normally abut closely, especially an exaggerated space between the incisor and canine
teeth in the upper jaw. The condition was evident in the dentition of certain of the Spice
Girls, a British rock band, and perceived by
devotees as so "cool" thatthey flocked to dentists to have their teeth parted in imitation,
diastole is a direct borrowing ofthe Greek word
meaning "a distinction or difference" and is
a combination dia-, "apart," + stellein, "to
put." "Setting apart" implies introducing or
expanding a pause between a sequence of
circumstances or events. It is in this sense
that "diastole" came to be, in physiology, the
name for the period of relaxation and dilatation of the heart muscle between systolic
contractions.
diathermy is a contrived term incorporating the
Greek therma, "heat," intensified by the prefix
dia-, thus referring to "penetrating heat."
diathesis is a Greek word meaning "an order of
arrangement," particularly in the sense of "a
disposition." Ancient writers conceived that
certain persons, because of their make-up or
temperament, were particularly disposed to
certain diseases. We use the term in much the
same way when we refer to a predisposition
as, for example, in "hemorrhagic diathesis."
dichotomy is taken from the Greek dikhotomos,
"divided," this being a combination of dicha,
"in two," + tome, "a cutting." A dichotomy,
then, results in two equal parts or a pair. In
biology, the term refers to branching equally
to become a pair. Used figuratively, "dichotomy" means a division into two usually
contradictory parts or opinions,
dicrotic is derived from the Greek di-, "two or
twice," + krotein, "to strike." The term has
been applied to a doubly peaked pulse wave.
Anacrotic (Greek ana-, "upward") means
the secondary impulse is on the ascending
limb of the pulse wave; catacrotic (Greek
kata, "down") means the secondary impulse
is on the descending limb,
dicumarol (see warfarin)
diet comes from the Greek diaita, "a way of
living or a mode of life." Originally the term
was used for a hygienic regimen generally;
only later it was restricted to a mode of eating
considered conducive to good health. Incidentally, this is quite distinct from "diet" as
the name for an assembly or parliament,
which is taken from the Latin dies, "day," implying that a formal meeting is held on an
appointed day.
digastric is the name of a muscle in the anterior neck that depresses the mandible and elevates the hyoid bone. It is so called because
it has two bellies, its name coming from the
Greek di-, "two," + gaster, "belly." Obviously,
despite its name, the muscle has nothing to
do with the stomach.
digestion is derived from the Latin digerere, "to
arrange, sort out, or distribute." Medieval
chemists used the term in the sense of “dissolving." In the 17th century a device was introduced whereby bones could be softened by
cooking under pressure, and this was called a
“digester." The early physiologists borrowed
the term in the belief that ingested food was
treated in the stomach in a manner similar
to digestion as carried out in the chemist's
laboratory. As it turned out, they may have
been closer to the mark than they might have
guessed.
digit is a contraction of the Latin digitus, "a
finger or a toe." A digitation is a finger-like
process, and to interdigitate means to
appear as interlocking fingers. "Digit" as a
term for a number came from the custom of
counting on one's fingers. Our normal allotment of ten fingers accounts for the decimal
system we use for numbering, as well as for
the metric system based on ten. (see finger)
digitalis comes from the Latin digitus, "finger."
The allusion is to the tubular blossoms ofthe
plant whose dried leaves, when pulverized,
provide the drug. The shape ofthe flowersuggests the empty finger of a glove. In part, this
explains the plant's common name, "the foxglove.” But why the “fox"? No one really
knows. By curious coincidence, "digitalis"
was proposed as the Latinized name for the
plant in the 16th century by Leonhard Fuchs
(1501-1566), a German botanist whose surname is German for "fox.” Apparently he
chose digitalis, a Latin way of saying "pertaining to the finger,” because the common
German name for the plantis Fingerhut, which
67
dilate dissect
means, literally, "a finger hat" or thimble. But
we are still left wondering why the foxglove
was so called as early as the 11th century.
dilate is a verb meaning "to enlarge or expand”
and is taken from the Latin dilatare meaning
the same and derived from di-, dis-, "apart," +
latus, "wide.” Often in medical parlance and
writing "dilation" and "dilatation" are used
more or less interchangeably. More precise
usage calls for "dilation" as the performance
and "dilatation" as the result. The instrument
used to accomplish the task is commonly
called a "dilator." But here the most persnickety word mavens step in to insist that "dilation" and “dilator" are wrongly formed from
the Latin (the first "-at-" being part ofthe word
and not contributing to the suffix "-tion,"
indicating an action). Therefore, we are instructed to always use "dilatation" in reference to either the procedure or its result and
"dilatator" for either the instrument orthe operator. To consistently use "dilatation" won't
be difficult, but, the sticklers notwithstanding,
it is doubtful "dilatator" will play in Peoria.
dimercaprol (see BAL)
diopter originated in the Greek dioptra, an
early optical instrument used for accurately
measuring heights and angles. "Diopter"
later was adopted as a name for the unit of
refractive power of lenses, expressed as a reciprocal ofthe focal length in meters.
diphtheria was given its name from the Greek
diphthera, "a prepared hide or leather," by
Pierre Bretonneau, a French physician, in the
1820s. The allusion is to the parchment-like
membrane in the throat characteristic of the
disease. Diphtheria was known to the ancient
Greeks and dreaded because of the high rate
ofmortality among children, butthey did not
call it by that name. To them it was the
"Egyptian disease" or "Syrian ulcer," yet another example of blaming a malady on those
from another country.
diplo- is a combining form taken from the
Greek diploos, "double or two-fold."
diplococcus is the name given to a bacterium
that looks like a pair of tiny berries (Greek
kokkos, "berry").
diploidy is the normal state of having paired
sets of homologous chromosomes in somatic
cells, (see -ploid)
diplopia was contrived as a combination of
diplo- + the Greek opsis, "vision," a term for
disunited visual images that first appeared in
print in the early 19th century,
dipsomania links the Greek dipsa, “thirst," +
mania, "madness." The term first appeared in
English in the mid-19th-century to mean "an
uncontrollable craving for drink," specifically
referring to alcoholic beverages, and deemed
a form ofinsanity,
dis- (see dys-)
disease comes from the Old French desaise, a
combination of des-, "away from," + aise,
"ease." In its early use, the term referred to
any tribulation that disturbed one's ease.
Only later did "disease" acquire its restricted
medical sense.
disk is a slightly abbreviated version of the
Greek diskos, "a circular, flat stone," which
the Greeks were much given to hurl. Sometimes the diskos had a hole in the center,
either for a strap by which to swing it or so it
could be used as a quoit (a doughnut-shaped
object to toss at a peg). The discus (Latin
counterpart) throw is still a feature ofmodern
Olympic games. "Disk" or "disc" now refers
to any circular, plate-like structure as, for example, the intervertebral disk,
disorienteddescribes a person who has lost his
sense of direction or relation to his surroundings. The term comes from a combination of
the Latin dis-, "deprived of," + oriens, “the
rising sun or the direction of east," the latter
being a present participle of oriri, "to rise." To
say a person is disoriented means, literally,
"He doesn't know which way is east," but in
more familiarterms, "He doesn't know which
end is up."
dispensary comes from the Latin dispensare,
"to weigh out." Originally the term was applied to a place where medicinal agents were
measured and distributed. Later, it came to
mean a place where the sick or injured were
treated but not confined as inpatients. In the
past, outpatient departments often were
called "dispensaries."
dissectisfrom the Latin dissecare, "to cut apart,"
this being a simple combination of dis-,
"apart," + secare, "to cut." An anatomic dissection, then, is "a cutting apart" of a body or
a part thereof for the purpose of identifying
<58
disseminate -dontal
and examining its components. Surgical dissection is a necessary preliminary to resection. (see resection)
disseminate (see semen)
distal (see proximal)
distill is derived from the manner in which
vapor from a heated liquid is condensed and
collected, drop by drop. The word is a combination of the Latin de-, "from," + stilla, "a
drop." To instill originally meant to introduce a liquid drop by drop,
diuresis combines the Greek dia-, "thoroughly,"
- ourein, "to urinate." There is a distinction
between stimulating the excretion and flow
of urine from the kidney and stimulating the
contraction ofthe urinary bladder in order to
cause its evacuation. By common acceptance, a diuretic agent is understood to be
that which promotes the formation of urine
by the kidney. An example, among others,
would be chlorothiazide. On the other hand,
bethanechol, which induces Smooth Muscle
contraction, is a bladder evacuant, not a diuretic. At one time a decoction of dandelion
leaves was used as a diuretic, hence the
French name for the weed: pissenlit, literally
"piss in bed."
diurnal (see journal)
diverticulum is a direct borrowing ofthe Latin
word for "a bypath orsmall wayside shelter,"
coming from the verb divertere, "to turn
aside." The suffix "-culum" implies the
diminutive and indicates that a diverticulum
is subsidiary to the main channel. It is importantto remember that "diverticulum" is the
Latin neuter singular and that "diverticula”
(not "diverticuli" or "diverticulae") is the
neuter plural, a point that many careless
speakers and writers seem to ignore,
dizzy (see vertigo)
DNA are initials now in common parlance and
nearly everyone knows they stand for deoxyribonucleic acid, the substance that
conveys genetic information. Johann-Friedrich
Miescher (1844-1895), a Swiss worker particularly interested in the chemistry of cell
nuclei, in 1870 managed to extract nearly
pure DNA from spermatozoa ofsalmon, cells
with exceedingly large nuclei. Miescher had
no idea of the significance of his accomplishment. DNA consists of two long chains of
nucleotides, twisted in the shape of a double
helix and made up ofsequences of complementary pyrimidine base pairs: adenine and
thymidine or cytosine and guanine. Adenine
was originally isolated in 1885 from a nucleic
acid found in beef pancreas, hence its name
indicating a product of a gland (see adeno-).
Cytosine (1894) is a name derived by linking cyt- + (rib)os(e) + -ine. Guanine was identified in bird droppings in 1844 and named
from Spanish guano, "bird dung," taken from
the Quechua huanu. Quechuan is an Incan
language, and vast deposits of guano were
discovered by Spaniards on islands off the
coast of Peru. Thymine was given its name
in 1894 when first isolated from the thymus
glands of calves.
doctor is taken from the Latin docere, "to
teach." In years past, "doctor" was a title of
courtesy and respect bestowed on a learned
man. Later, it became the title accorded a
holder of the highest academic degree.
Meanwhile, "doctor" acquired, mainly among
speakers of English, a specifically medical
connotation. Probably this was because, of
all learned scholars, only members of the
medical faculty were figures familiar to the
public at large. In no language other than
English is a practitioner of medicine commonly referred to as a "doctor" (see iatr-) or
is "doctor" used as a verb, meaning “to treat
or alter." (see leech)
dol is an arbitrary unit used to express intensity
of pain. It is an elision of the Latin dolor,
"pain."
dolicho- is a combining form derived from the
Greek dolichos, "long." Thus, dolichocephalic refers to a long head, and dolichocolon is an unusually long and redundant
large intestine.
doll's eyes in medical parlance is an expression
that describes peculiar movement of the eyes
in patients with certain types of metabolic
coma, notably in hypoglycemia and hepatic
encephalopathy. Moving the head from one
side to the other will elicit abrupt movement
ofthe eyes to the opposite side, suggesting the
mechanical movement of doll's eyes, a sign
of cortical depression with intact brainstem
connections.
-dontal (see tooth)
69
DA; PIF (Dopamine ; Prolactin Inhibiting Factor) drosophila
DA; PIF (Dopamine ; Prolactin Inhibiting Factor) is an immediate metabolic precursor
of epinephrine and norepinephrine, hence
 important in central sympathomimetic actions. Sometimes called by its nickname
"dopa," it has nothing to do with "dope.” It is
merely a somewhat unfortunate acronym for
3,4-dihydroxyphenylethylamine.
dope comes from the Dutch doop, meaning "a
sauce or viscous liquid." The term became
applied to narcotics because raw opium when
heated becomes a thick liquid. Later, any
substance having a numbing or stupefying
effect became known as "dope." By extension, a person afflicted with a narcotic effect
was called, in slang, "a dopehead" or simply
"a dope." But there is more to the vagaries of
this little word. Unscrupulous racehorse promoters found they could often ensure the outcome of a race by giving a drug to the mount
pre-selected for winning. Anyone privy to this
illicit information was said to have "the
inside dope." Soon, any worthwhile intelligence came to be called "the dope."
doppler describes a recordable effect ofsound
or ultrasound waves when they emanate
from or are directed at a moving object. The
technique has been applied to medical diagnosis, especially in determining the extent
and direction of blood flow within a given
vessel. The term is taken from the name of
Christian Doppler (1803-1853), an Austrian
mathematician who was the first to explain
why, for example, the pitch of a locomotive
whistle is higher when the train is approaching the listener than when the train is speeding away.
dorsum is Latin for "back.” Thus, the dorsum
of the hand or foot is the "back" ofthat part,
opposite the palm or sole. The adjective
dorsal is understood to pertain to the back
of any part, but especially to the back of the
thorax. The dorsal vertebrae are the thoracic vertebrae. "Dorsal" also is used to mean
"posterior,” as in the dorsal roots ofthe spinal
nerves. Incidentally, to endorse a check is to
sign one's name on the back ofthe document,
dose is said to have had its origin in the postulated Indo-European root do, "to give." A descendent is the Greek dosis, "that which is
given." A related word is the Latin donare, "to
bestow," and from this we derive "donate." A
dose, then, is the "giving" of a specified
amount of a medicine.
douche is the French word for "a shower-bath"
and can be traced to the Latin ductus, the
past participle of ducere, "to lead." A douche,
then, is a stream of water or watery solution
directed to a body part or cavity for the purpose of cleansing.
Down syndrome (see mongolism)
dram is an almost forgotten unit of measure. It
came originally from the Greek drachme, a
coin approximately equivalent to a Roman
denarius. The coin also was used as a weight,
and later a "drachma" or dram became oneeighth of an ounce as an apothecary's weight
(but one-sixteenth of an avoirdupois ounce).
Before adoption of the metric system, a dram
of fluid was commonly taken to be one teaspoonful (nearly equivalentto 5 mL). One tablespoonful (approximately equivalent to 15
mL) is one-half a fluid ounce. The use ofteaspoons and tablespoons for prescribed doses
of liquid medicines is common because these
utensils are readily available for measurement in most households. Ounce comes
from the Latin uncia, "a twelfth," this being
one-twelfth of a Roman libra or pound (hence
the abbreviation "lb." for pound). One must
keep in mind the differences between liquid
and dry measurements and between Roman
and English custom.
dropsy is a now archaic term for swelling in
body tissues due to accumulation of excess
fluid. Its use in English comes through the
French hydropsie, from the Greek hydrops,
hydor being the Greek word for water. In
former times, "dropsy" often was used as a
diagnosis in itself. Now we refer to edema, ascites, or anasarca as more descriptive signs,
and we require a designation of the underlying cause, such as congestive heart failure or
cirrhosis, as the diagnosis. This refined perception accounts for the disuse of "dropsy."
(see hydrops)
drosophila is the proper name of the common
fruit-fly, a ubiquitous denizen of biology laboratories and produce stands. Its full name
is Drosophila melanogaster, literally "blackbellied dew-sipper" (Greek drosos, "dew," +
philos, "affinity"; melanos, "black," + gaster,
"belly").
70
drug dystrophy
drug is a word that etymologists either avoid or
treat at undue length. The reason is that no
one can be sure of its origin. The Middle
English droge and the Old French drogue both
referred to chemical substances variously
used as medicaments or dyes. A related word
is the Dutch droog, "dry," as applied to any
dessicated substance, such as herbs,
duct is a contraction ofthe Latin ductus, "a drawing or a leading," which is related, in turn, to
the verb ductere, "to draw, to lead, orto escort."
However, Latin authors never used ductus
when they referred to a conduit for fluids.
Rather, they used canalis, "a pipe or gutter.”
duodenum began as the Greek dodeka-daktulon,
"twelve fingers," the idea being thatthe most
proximal portion of the small intestine from
the pylorus to the ligament of Treitz is about
twelve finger-breadths long. This came to be
translated, through the Arabic, as the Late
Latin duodenum. In classical Latin this would
have been duodecim, "twelve" (from duo,
"two," + decern, "ten"). In German, the duodenum is der Zwolffingerdarm, "the twelvefinger intestine."
dura mater is the name for the tough, outer
membrane encasing the brain and spinal
cord. It is composed of the Latin words dura,
"hard or tough," and mater, "mother." This
makes little sense until one knows that the
Latin dura mater is a literal translation of its
precedent, the Arabic term which meant
"strong mother" (in a sense suggesting 'protector') of the brain." The Arabs liked to use
their word for "mother" as a figure ofspeech,
dys- is an inseparable combining form, originating in the Greek, that confers a bad sense
on whatever word to which it is attached.
"Dys-" conveys a meaning of defective, difficult, ill, or painful. There are a host of medical terms beginning with "dys-." Some of
them are closely related to Greek words.
Some "dys-" words are more tortuously contrived. An example is dysfunction, to refer
to anything that goes wrong. Incidentally,
"dys-" is notto be confused with dis-, a prefix
borrowed from the Latin and meaning "apart,
asunder, deprived of."
dyschezia (see -chezia)
dyscrasia is an almost direct borrowing ofthe
Greek dyskrasia, "a bad mixture of humors, a
bad temperament"; the Greek krasis means
"mixture or make-up." The term originally
referred to any diseased condition but now,
for some obscure reason, is restricted to
hematology, as in "blood dyscrasias."
dysentery is the condition of a painful gut,
usually attended by diarrhea. To the Greeks
dysenteria {dys- + enteron, "intestine") meant
any sort of bowel complaint,
dysgeusia combines dys- + Greek geusis,
"taste"and is a pretentious way ofsaying "a
bad taste in the mouth."
dyskinesia is a direct borrowing of the Greek
word for "difficulty of movement" {dys- +
kinesis, "motion"). The term includes a variety of impairments in voluntary and involuntary muscular contractions,
dyslexia joins dys- + Greek lexis, "diction" to
designate an impaired ability to read or write
words, a familial disorder more frequent in
boys, (see alexia)
dyspareunia is taken from the Greek dyspareunos, literally "ill-mated." The Greek pareunos
{para-, "beside," + eunos, "bed") means "lying
beside." Now the term is restricted to painful
sexual intercourse.
dyspeptic describes a nondescript digestive
malaise. The term was contrived by combining dys- + Greek pepsis, "digestion."
dysphagia means difficult or impaired swallowing {dys- + Greek phagein, "to swallow”).
Aphagia is total inability to swallow,
dyspnea relates to the Greek dyspnoia {dys- +
pnoia, "breathing"), and both mean "difficult
or labored breathing." To detect subtly labored breathing, try breathing in synchrony
with your patient. You may be surprised how
readily dyspnea thereby becomes evident,
dystrophy is an abnormal growth or development, from whatever cause. The term combines dys- + Greek trophe, "nourishment."