Pronunciation: (fôr, fōr), [key]
1. a cardinal number, three plus one.
2. a symbol of this number, 4 or IV or IIII.
3. a set of this many persons or things.
4. a playing card, die face, or half of a domino face with four pips.
5. fours, Jazz.alternate four-bar passages, as played in sequence by different soloists: with guitar and piano trading fours.
a. an automobile powered by a four-cylinder engine.
b. the engine itself.
7. on all fours. See all fours (def. 3).
amounting to four in number.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.