Webster's Revised Unabridged Dictionary · 1913

Ace

Ace (ās) , noun

[Old English as, French as, from Latin as, assis, unity, copper coin, the unit of coinage. Compare As.]

1.
A unit; a single point or spot on a card or die; the card or die so marked; as, the ace of diamonds.
2.
Hence: A very small quantity or degree; a particle; an atom; a jot.
I 'll not wag an ace further. — Dryden
3.
(Sport) A single point won by a stroke, as in handball, rackets, etc.; in tennis, frequently, a point won by a service stroke.
Collocations (2)
To bate an ace , to make the least abatement. [Obs.]
Within an ace of , very near; on the point of. — W. Irving

ace , adjective

1.
of the highest quality

ace , verb

to get a grade of "A"; as, to ace an exam. [Colloquial]