1911 Encyclopædia Britannica/Deuce
DEUCE (a corruption of the Fr. deux, two), a term applied to the "two" of any suit of cards, or of dice. It is also a term used in tennis when both sides have each scored three points in a game, or five games in a set; to win the game or set two points or games must then be won consecutively. The earliest instances in English of the use of the slang expression "the deuce," in exclamations and the like, date from the middle of the 17th century. The meaning was similar to that of "plague" or "mischief" in such phrases as "plague on you," "mischief take you" and the like. The use of the word as an euphemism for "the devil" is later. According to the New English Dictionary the most probable derivation is from a Low German das daus, i.e. the "deuce" in dice, the lowest and therefore the most unlucky throw. The personification, with a consequent change of gender, to der daus, came later. The word has also been identified with the name of a giant or goblin in Teutonic mythology.