[four] n [ME, fr. four adj., fr. OE feower; akin to OHG fior four, L quattuor, Gk tessares, tettares] (bef. 12c) 1: one more than three
2: the fourth in a set or series "the ~ of hearts"
3: something having four units or members: as a: a 4-oared racing shell or its crew b: a 4-cylinder engine or automobile -- four adj -- four pron, pl in constr