1. a social gathering or outing for men only.
2. a party given a bachelor by his male friends before his marriage, often on the night before the wedding, ranging from a formal gathering to a night of carousing.
3. a gathering for men only, esp. one for the purpose of watching sexually titillating movies or exhibitions.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.