--noun (singular: ace; plural: aces)

1. 1: the smallest whole number or a numeral representing this number.
2. adept: someone who is dazzlingly skilled in any field.
3. angiotensin-converting enzyme: proteolytic enzyme that converts angiotensin I into angiotensin II.
4. allied command europe: a major strategic headquarters of NATO; safeguards an area extending from Norway to Turkey.
5. one of four playing cards in a deck having a single pip on its face.
6. a serve that the receiver is unable to reach.

--verb

7. to score an ace against.
  • "He aced his opponents."
8. to succeed at easily.
9. to play (a hole) in one stroke.
10. to serve an ace against (someone) .

--adj.

11. of the highest quality.
  • "An ace reporter."
c.1300, from Old French as "one at dice", from Latin as (genitive assis) "a unit", from the name of a small Roman coin, perhaps originally Etruscan and related to Greek eis "one." It meant the side of the die with only one mark before it meant the playing card. Since this was the lowest roll at dice, ace was used metaphorically in Middle English for "bad luck;" but as the ace is often the highest playing card, the extended senses based on "excellence, good quality" arose 18c. as card-playing became popular. Meaning "outstanding pilot" dates from 1917 (technically, in WWI aviators' jargon, one who has brought down 10 enemy planes). Sports meaning of "point scored" (1819) led to that of "unreturnable serve" (1889). The verb meaning "to score" (in sports) is first attested 1923, and led to the extended student slang sense of "get high marks" (1959). Ace in the hole "concealed advantage" is attested from 1915.

An ace is a playing card. In the standard French deck, an ace has a single suit symbol located in the middle of the card, sometimes large and decorated, especially in the case of the ace of spades. This embellishment on the ace of spades started when King James VI of Scotland and I of England required an insignia of the printing house to be printed on the ace of spades.