Deuce \Deuce\, n. [Cf. LL. dusius, Armor, dus, te[^u]z, phantom, specter; Gael. taibhs, taibhse, apparition, ghost; or fr. OF. deus God, fr. L. deus (cf. Deity).]

The devil; a demon. [A euphemism, written also deuse.]

[Low]

Source: Webster's Revised Unabridged Dictionary (1913)
 

Deuce \Deuce\ (d[=u]s), n. [F. deux two, OF. deus, fr. L. duo. See Two.]

1. (Gaming) Two; a card or a die with two spots; as, the deuce of hearts.

2. (Tennis) A condition of the score beginning whenever each side has won three strokes in the same game (also reckoned ``40 all''), and reverted to as often as a tie is made until one of the sides secures two successive strokes following a tie or deuce, which decides the game.

Source: Webster's Revised Unabridged Dictionary (1913)