/ djuːs; NAmE duːs/ noun
1.
[ U , C ] ( in tennis ) the situation when both players have 40 as a score, after which one player must win two points one after the other in order to win the game
2.
[ C ] ( NAmE ) a playing card with two pips on it :
the deuce of clubs
3.
the deuce [ sing. ] ( old-fashioned , informal ) used in questions to show that you are annoyed :
What the deuce is he doing?
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WORD ORIGIN
senses 1 to 2 late 15th cent.: from Old French deus two, from Latin duos .
sense 3 mid 17th cent.: from Low German duus , probably of the same origin as deuce two (two aces at dice being the worst throw).