The Collaborative International Dictionary of English v.0.48:
3-hitter \3-hitter\ n. 1. a game in which a pitcher allows the opposing team only 3 hits. Syn: three-hitter [WordNet 1.5]WordNet (r) 3.0 (2006):
3-hitter n 1: a game in which a pitcher allows the opposing team only 3 hits [syn: three-hitter, 3-hitter]