The Collaborative International Dictionary of English v.0.48:
four-hitter \four-hitter\ n. (Baseball) A game in which a pitcher allows the opposing team four hits; as, he pitched a four-hitter. Syn: 4-hitter. [WordNet 1.5]WordNet (r) 3.0 (2006):
four-hitter n 1: a game in which a pitcher allows the opposing team 4 hits [syn: four-hitter, 4-hitter]