- –noun1.a playing card or die marked with or having the valueindicated by a single spot: He dealt me four aces in the firsthand.2.a single spot or mark on a playing card or die.3.(in tennis, badminton, handball, etc.)a.Also called service ace. a placement made on a service.b.any placement.c.a serve that the opponent fails to touch.d.the point thus scored.4.a fighter pilot credited with destroying a prescribed numberor more of enemy aircraft, usually five, in combat.5.a very skilled person; expert; adept: an ace at tap dancing.6.Slang . a one-dollar bill.7.Slang . a close friend.8.Golf .a.Also called hole in one. a shot in which the ball isdriven from the tee into the hole in one stroke: He hit a225-yard ace on the first hole.b.a score of one stroke made on such a shot: to card anace.9.Slang . a barbiturate or amphetamine capsule or pill.10.a very small quantity, amount, or degree; a particle: notworth an ace.11.Slang . a grade of A; the highest grade or score.–verb (used with object)12.(in tennis, badminton, handball, etc.) to win a point against(one's opponent) by an ace.13.Golf . to make an ace on (a hole).14.Slang . to cheat, defraud, or take advantage of (often fol. byout ): to be aced out of one's inheritance; a friend who acedme out of a good job.15.Slang .a.to receive a grade of A, as on a test or in a course(sometimes fol. by out ).b.to complete easily and successfully: He aced everyphysical fitness test they gave him.–adjective16.excellent; first-rate; outstanding.—Verb phrase17.ace it, Slang . to accomplish something with completesuccess: a champion who could ace it every time.—Idioms18.ace up one's sleeve, an important, effective, or decisiveargument, resource, or advantage kept in reserve untilneeded.19.be aces with, Slang . to be highly regarded by: The bosssays you're aces with him.20.easy aces, Auction Bridge . aces equally divided betweenopponents.21.within an ace of, within a narrow margin of; close to: Hecame within an ace of winning.