Webster's New World Medical Dictionary

cohort
In a clinical research trial, a group of
study participants or patients.
coinsurance
See 
copayment.
coitus
Sexual intercourse.
coitus interruptus
Sexual intercourse in which,
as a birth-control measure, the male attempts to
withdraw the penis before ejaculation. It is not usu-
ally an effective means of birth control because
sperm are present in preejaculate fluid produced
during intercourse. See also 
birth control.
colchicine
A plant substance that is used in clin-
ical medicine for the treatment of the inflammation,
such as from gouty arthritis, and in the laboratory
to arrest cells during cell division by disrupting the
spindles so that their chromosomes can be visual-
ized.
COLD
Chronic obstructive lung disease.
cold, common
A contagious viral upper respira-
tory tract infection. The common cold can be
caused by many different types of viruses, and the
body can never build up resistance to all of them.
For this reason, colds are a frequent and recurring
problem. Going out into cold weather has no effect
on causing a cold. Antibiotics do not cure or
shorten the duration of the illness.
cold, June
See 
hay fever.
cold, summer
See 
allergic rhinitis.
cold injury
An injury caused by exposure to
extreme cold that can lead to loss of body parts and
even to death. Examples of cold injury are chilblain,
trench foot, and frostbite. Cold injury occurs with
and without freezing of body tissues. The young and
the elderly are especially prone to cold injury, and
alcohol consumption increases the risk of cold
injury. It is important not to thaw an extremity if
there is a risk of it refreezing. The extremity should
be protected from trauma and gradually rewarmed.