Webster's New World Medical Dictionary

Raeder syndrome
See 
cluster headache.
ragweed
Any of several weedy composite herbs
that produce a pollen to which many people are
allergic. Of all allergy sufferers in the US, 75 percent
are allergic to ragweed.
RAI
Radioactive iodine.
rale
An abnormal lung sound that can be heard
through a stethoscope. Rales may be sibilant
(whistling), dry (crackling), or wet (sloshy),
depending on the amount and density of fluid
refluxing back and forth in the air passages.
Ramsey Hunt syndrome
A herpesvirus (specif-
ically, by the varizella-zoster virus or VZV) infection
of the geniculate nerve ganglion, which causes
paralysis of the facial muscles on the same side of
the face as the infection. It is usually associated with
an unusual rash (composed of vesicles, or tiny
fluid-filled bumps, in the skin) in or around the ear
and sometimes on the roof of the mouth. Ramsey
Hunt syndrome is commonly more painful and
more debilitating than Bell’s palsy. Treatment with
steroids and antiviral agents, such as acyclovir
(brand name: Zovirax) may improve recovery and
lessen pain.
ramus
In anatomy, a branch, such as a branch of
a blood vessel or nerve. For example, the ramus
acetabularis arteriae circumflexae femoris medialis
is the branch of an artery that goes to the socket of
the hip joint. The plural of ramus is rami.
ramus of the mandible
One of the two promi-
nent, projecting back parts of the horseshoe-shaped
lower jaw bone.
random
Determined solely by chance.
random mating
Totally haphazard mating, with
no regard to the genetic makeup (genotype) of the
mate, so that any sperm has an equal chance of fer-
tilizing any egg. Random mating rarely, if ever,