'sex act' definitions:

Definition of 'sex act'

From: WordNet
The act of sexual procreation between a man and a woman; the man's penis is inserted into the woman's vagina and excited until orgasm and ejaculation occur [syn: sexual intercourse, intercourse, sex act, copulation, coitus, coition, sexual congress, congress, sexual relation, relation, carnal knowledge]

Synonyms of 'sex act'

From: Moby Thesaurus