n. & v.
--n.
1. a person who shares or takes part with another or others, esp. in a business firm with shared risks and profits.
2 a companion in dancing.
3 a player (esp. one of two) on the same side in a game.
4 either member of a married couple, or of an unmarried couple living together.
--v.tr.
1. be the partner of.
2 associate as partners.
Derivatives:
partnerless adj.
Etymology: ME, alt. of parcener joint heir, after PART