dou·ble / ˈdəbəl/ • adj. 1. consisting of two equal, identical, or similar parts or things: the double doors. ∎  having twice the usual size, quantity, or strength: she sipped a double brandy. ∎  designed to be used by two people: a double bed. ∎  having two different roles or interpretations, esp. in order to deceive or confuse: the furtive double life of a terrorist.2. having some essential part or feature twice, in particular: ∎  (of a flower variety) having more than one circle of petals: large double blooms. ∎  (of a domino) having the same number of dots on each half. ∎  used to indicate that a letter or number occurs twice in succession: “otter” is spelled with a double t.3. Mus. lower in pitch by an octave.• twice as much or as many: the jail now houses almost double the number of prisoners it was designed for I'll pay double what I paid last time.• adv. at or to twice the amount or extent: you have to be careful, and this counts double for older people. ∎  as two instead of the more usual one: she thought she was seeing double.• n. 1. a thing that is twice as large as usual or is made up of two standard units or things: join the two sleeping bags together to make a double. ∎  a double measure of liquor. ∎  a thing designed to be used by two people, esp. a bed or a hotel room: we'll use the bunk beds, you take the double| our rates are $200 per night for a double. ∎ Baseball a hit that allows the batter to reach second base safely: Sabo came home on a double by O'Neill. ∎  a system of betting in which the winnings and stake from the first bet are transferred to a second. ∎  Bridge a call that will increase the points won if the declarer is successful, or increase the penalty points won by the defenders if the declarer fails to make the contract. ∎  Darts a hit on the narrow ring enclosed by the two outer circles of a dartboard, scoring double.2. a person who looks exactly like another: you could pass yourself off as his double. ∎  a person who stands in for an actor in a film. ∎  an apparition of a living person: she had seen her husband's double.3. (doubles) (esp. in tennis and badminton) a game or competition involving sides made up of two players: the semifinals of the doubles. • pron. a number or amount that is twice as large as a contrasting or usual number or amount: he paid double and had a room all to himself.• v. 1. [intr.] become twice as much or as many: profits doubled in one year. ∎  [tr.] make twice as much or as many of (something): Clare doubled her income overnight. ∎  [tr.] archaic amount to twice as much as: thy fifty yet doth double five and twenty. ∎  (double up) use the winnings from a bet as stake for another bet. ∎  (of a member of the armed forces) move at twice the usual speed; run: I doubled across the deck to join the others. ∎  (double up) share a room: “Where's Jimmy going to sleep?” “He can double up with Bert.” ∎ Baseball (of a batter) get a two-base hit: Strawberry doubled with two outs. ∎  Bridge make a call increasing the value of the penalty points to be scored on an opponent's bid if it wins the auction and is not fulfilled. ∎ inf. go out on a double date: they doubled with his sister and her oafish boyfriend.2. [tr.] fold or bend (paper, cloth, or other material) over on itself: the muslin is doubled and then laid in a sieve over the bowl. ∎  [intr.] (double up) bend over or curl up, typically because one is overcome with pain or mirth: Billy started to double up with laughter. ∎  clench (a fist): he had one arm around her and the other fist doubled. ∎  [intr.] (usu. double back) go back in the direction one has come: he had to double back to pick them up. ∎  Naut. sail around (a headland): we struck out seaward to double the headland of the cape.3. [intr.] (of a person or thing) be used in or play another, different role: a laser printer doubles as a photocopier. ∎  [tr.] (of an actor) play (two parts) in the same piece. ∎  Mus. play two or more musical instruments. ∎  [tr.] Mus. add the same note in a higher or lower octave to (a note).PHRASES: on the double at running speed; very fast: he disappeared on the double. ∎  without hesitation; immediately he summoned his officers on the double.double or nothing a gamble to decide whether a loss or debt should be doubled or canceled.DERIVATIVES: dou·bler n.dou·bly adv.