noun.
In human sexual behavior, the acts at the beginning of a sexual encounter that serve to build up sexual arousal, sometimes in preparation for sexual intercourse or another act meant to bring about orgasm.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
noun.
mutual sexual fondling prior to sexual intercourse
Word Usage
"Her fertility is also increased if the couple engages in foreplay beforehand, of which oral sex can be considered a variety."