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