Webster's New World Medical Dictionary

clinical research trial
A study that is intended
to evaluate the safety and effectiveness of medica-
tions or medical devices by monitoring their effects
on large groups of people. Studies may be con-
ducted by government health agencies (such as the
National Institutes of Health [NIH]), researchers
affiliated with hospital or university medical pro-
grams, independent researchers, or individuals
from private industry. Usually volunteers are
recruited, although in some cases research partici-
pants may be paid. For some patients, clinical
research trials represent an avenue for receiving
promising new therapies that would not otherwise
be available. Patients with difficult-to-treat or
“incurable” diseases may pursue participation in
clinical research trials if standard therapies are not
effective.
clinical trial
See 
clinical research trial.
clip
A device used to hold something or things
together. For example, a surgical clip may be used
to prevent a blood vessel from bleeding into the
brain, or in a vasectomy to pinch together the sides
of the vas deferens.
clitoridectomy
The surgical excision (removal)
of the clitoris to reduce a woman’s ability to be sex-
ually stimulated during intercourse. Also known as
female circumcision and female genital mutilation.
See also 
circumcision, female.
clitoris
A small mass of erectile tissue in the
female that is situated at the anterior apex of the
vulva, near the meeting of the labia majora (vulvar
lips). Like the penis, the clitoris is highly sensitive to
stimulation during sex. The clitoris corresponds to
the penis in the male.
CLL
Chronic lymphocytic leukemia. See
leukemia, chronic lymphocytic.
clone 1
A replica. For example, a clone can be
made of a group of bacteria or a macromolecule
such as DNA.