Very close to, within a narrow margin of. This term refers to the ace of dice (not playing cards)—that is, the one pip on a die. Since the lowest number one can throw with a pair of dice is two (two aces), such a throw is within an ace of one. The term was transferred to other near misses by 1700 or so. Thomas Browne wrote, “I was within an ace of being talked to death” (letter, 1704), and Alexander Pope, “I was within an ace of meeting you” (letter, 1711).