ace (ās)
n.

1. 1. A single spot or pip on a playing card, die, or domino.
   2. A playing card, die, or domino having one spot or pip.
2. In racket games:
   1. A serve that one's opponent fails to hit.
   2. A point scored by such a serve.
3. The act of hitting a golf ball in the hole with one's first shot.
4. A military aircraft pilot who has destroyed five or more enemy aircraft.
5. An expert in a given field.

adj.
Top-notch; first-rate.

tr.v., aced, ac·ing, ac·es.

1. To serve an ace against in racket games.
2. To hit an ace on (a hole) in golf.
3. Slang. To get the better of (someone): a candidate who aced his opponents in the primaries.
4. Slang.
   1. To receive a grade of A on: She aced the exam.
   2. To perform with distinction on: aced the interview.

idioms:

ace in the hole (or up one's sleeve)

1. A hidden advantage or resource kept in reserve until needed.

within an ace of

1. On the verge of; very near to: came within an ace of losing the election.

[Middle English as, from Old French, from Latin, unit.]

---

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.

---