(1):
(n.) Arrest of development of any organ, so that it remains an imperfect formation or is absorbed.
(2):
(n.) Any fruit or produce that does not come to maturity, or anything which in its progress, before it is matured or perfect; a complete failure; as, his attempt proved an abortion.
(3):
(n.) The act of giving premature birth; particularly, the expulsion of the human fetus prematurely, or before it is capable of sustaining life; miscarriage.
(4):
(n.) The immature product of an untimely birth.