ace / ās/ • n. 1. a playing card with a single spot on it, ranked as the highest card in its suit in most card games: the ace of diamonds. ∎  informal Golf a hole in one. 2. inf. a person who excels at a particular sport or other activity: a motorcycle ace. ∎  a pilot who has shot down many enemy aircraft, esp. in World War I or World War II. 3. (in tennis and similar games) a service that an opponent is unable to return and thus wins a point.• adj. inf. very good: an ace swimmer.• v. [tr.] inf. (in tennis and similar games) serve an ace against (an opponent). ∎  Golf score an ace on (a hole) or with (a shot). ∎  get an A or its equivalent in (a test or exam): I aced my grammar test. ∎  (ace someone out) outdo someone in a competitive situation.PHRASES: an ace up one's sleeve (or in the hole) a plan or piece of information kept secret until it becomes necessary to use it.hold all the aces have all the advantages.play one's ace use one's best, often secret, resource.

ACE Astronomy Advanced Composition Explorer
• advanced computing environment
• Engineering advanced cooled engine
• (eɪs) Advisory Centre for Education
• Med. alcohol-chloroform-ether (anaesthetic)
• (eɪs) Allied Command Europe
• American Council on Education
• (eɪs) Biochem., Med. angiotensin-converting enzyme (as in ACE inhibitor)
• (USA) Army Corps of Engineers
• Association for the Conservation of Energy
• (Member of the) Association of Conference Executives
• Association of Consulting Engineers
• Association of Cultural Exchange
• Australian College of Education
• (eɪs) Computing Automatic Computing Engine

ACE Acronym for Automatic Computing Engine. An electronic stored-program computer designed in 1945–46 by Alan Turing while he was at the National Physical Laboratory (NPL), near London. The prototype version Pilot ACE was built at the NPL, ran its first program in 1950, and was in full-time use in 1952. The final version was working by 1957. A production model of Pilot Ace, called DEUCE, was marketed by the English Electric company.

ACE Angiotensin converting enzyme, in the blood vessels of the lungs, which activates angiotensin. Many of the drugs for treatment of hypertension are ACE inhibitors.

ace throw of one at dice XIII; playing-card bearing one pip (reckoned as of the highest value) XVI; the highest or best XVIII. ME. a(a)s —(O)F. as :- L. as, ass- unit(y).