Amenorrhea

Also menstrual block. Absence of menstruation. Between menarche and menopause menstruation normally ceases only in pregnancy. Amenorrhea is the continuing absence of menstruation after the age of eighteen or the abnormal cessation of menstrual periods for at least three months in women who are neither pregnant nor lactating. Rarely, lifelong absence of menstruation is unaccompanied by impairment of reproductive function. See the entries listed below.

Etymology

Chin 经 jīng, warp, rule, regular, channel (meridian); to pass; 闭 bì, close, shut, end.