Webster's New World Medical Dictionary

digit
A finger or toe.
digit, supernumerary
An extra finger or toe.
digital rectal exam
A routine exam in which a
physician inserts a lubricated, gloved finger into the
rectum and feels for abnormal areas to detect rectal
cancer and, in a man, inflammation, enlargement,
or cancer of the prostate as well as nerve problems
indicated by reduction of the normal tone of the
muscles of the rectal sphincter.
digitalis
A chemical from the dried leaf of the
common foxglove (Digitalis purpurea) plant that is
to used to strengthen the force of the heartbeat. The
Scottish physician William Withering discovered this
use for digitalis in the late 1700s. Digitalis, its com-
ponents, and their derivatives have long been used
to treat congestive heart failure and slow the speed-
ing heart so it is more efficient.
dilatate
In medicine, to enlarge or expand. Also
known as dilate.
dilatation
The process of enlargement or expan-
sion. Also known as dilation.
dilate
To stretch or enlarge. Also known as
dilatate.
dilating
The widening and opening of an open-
ing, such as the cervix or esophagus. For example,
the amount of widening can be described in terms
of the number of fingers that could fit in the cervi-
cal opening, or it is described in centimeters.
dilation
See 
dilatation.
dilation, pupil 1
A type of eye examination that
enables an eye-care professional to see more of the
retina, the light-sensitive layer of tissue at the back
of the eye. Dilating the pupil permits the retina to be
examined for signs of disease. To dilate the pupil,
drops are placed into the eye. 
2
A normal
response of the iris to a decrease in light exposure.