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