- A unit; a single point or spot on a card or die; the card or die so marked; as, the ace of diamonds.
- Hence: A very small quantity or degree; a particle; an atom; a jot."I 'll not wag an ace further." [Dryden.]
- [Sport] A single point won by a stroke, as in handball, rackets, etc.; in tennis, frequently, a point won by a service stroke.
Etymology: OE. as, F. as, fr. L. as assis, unity, copper coin, the unit of coinage. Cf. As