Webster's New World Medical Dictionary

orbital ridge
The bony ridge beneath the eyebrow.
orchidectomy
The surgical removal of one or
both testes.
orchiectomy
Orchidectomy.
orchiopathy
Any and all diseases of the testes.
orchiopexy
Surgery to bring an undescended
testicle down into the scrotum.
orchitis
Inflammation of the testis. Causes of
orchitis include mumps and other infections; dis-
eases, such as polyarteritis nodosa; and injury.
organ
A relatively independent part of the body
that carries out one or more special functions.
Examples of organs include the eyes, ears, heart,
lungs, and liver.
organic 1
A chemical compound that contains
carbon. 
2
Related to an organ.
3
Grown or pre-
pared without the use of chemicals or pesticides, as
in organic food.
organic brain syndrome
Psychiatric or neuro-
logical symptoms that arise from damage to or dis-
ease in the brain. Also known as organic mental
disorder.
organotherapy
The use of extracts of animal
glands or organs to treat disease. Pituitary extracts
from pigs, for example, were used for many years to
treat hormone disorders.
organs of reproduction, female
See 
female
organs of reproduction.
organs of reproduction, male
See 
male
organs of reproduction.
orgasm
A series of muscle contractions in the
genital region that is accompanied by sudden
release of endorphins. Orgasm normally accompa-
nies male ejaculation as a result of sexual stimula-
tion, and it also occurs in females as a result of
sexual stimulation.
orifice
An opening. For example, the mouth is an
orifice.