from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Masturbation.
- n. Coitus interruptus.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. ejaculating outside the vagina during intercourse; (the performing of) coitus interruptus
- n. masturbation
from the GNU version of the Collaborative International Dictionary of English
- n. Self-pollution; masturbation.
from The Century Dictionary and Cyclopedia
- n. Gratification of the sexual appetite in an unnatural way.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. manual stimulation of the genital organs (of yourself or another) for sexual pleasure
- n. a method of birth control in which coitus is initiated but the penis is deliberately withdrawn before ejaculation
After Onan, son of Judah (Genesis 38:9).(American Heritage® Dictionary of the English Language, Fourth Edition)
From the biblical name Onan: In the Book of Genesis, Onan, son of Judah, in fulfillment of the laws of levirate marriage was to impregnate his brother Er's widow, Tamar, in order to raise offspring from the union in his brother's name. In order to avoid raising descendants for his late brother, however, Onan spilled his semen on the ground when he went in to his brother's wife, so that he would not give offspring to his brother. (Genesis 38:9). Thus the word Onanism was coined, meaning ejaculating outside the vagina, or masturbation (because this also spills semen, rather than using it for procreation). (Wiktionary)