n. [ L. abortio, fr. aboriri. See Abort. ] 1. The act of giving premature birth; particularly, the expulsion of the human fetus prematurely, or before it is capable of sustaining life; miscarriage. [ 1913 Webster ]

2. The immature product of an untimely birth; a fetus which has been delivered prematurely due to spontaneous or voluntary abortion, and is dead. [ 1913 Webster +PJC ]

3. (Biol.) Arrest of development of any organ, so that it remains an imperfect formation or is absorbed. [ 1913 Webster ]

4. 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. [ 1913 Webster ]

5. the removal of a fetus from the womb prior to normal delivery in a manner such as to cause the death of the fetus; also called voluntary abortion, or when performed by a physician, therapeutic abortion. [ PJC ]

In the 1913 Webster there was the following note appended to sense 1:
☞ It is sometimes used for the offense of procuring a premature delivery, but strictly the early delivery is the abortion, “causing or procuring abortion” is the full name of the offense. Abbott. [ PJC ]

6. something considered to be a repulsive or monstrous variant of a normal object; a monstrosity. [ PJC ]

a. Pertaining to abortion; miscarrying; abortive. Carlyle. [ 1913 Webster ]

n. One who performs or procures abortion; among medical personnel, also called an abortion provider. The word abortionist has negative connotations from the time when the practise was illegal in the United States, and the latter term is preferred among those who do not consider the procedure as morally reprehensible. [ 1913 Webster +PJC ]

n. same as abortionist. [ PJC ]