double

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Twice as much in size, strength, number, or amount.
• adjective Composed of two like parts.
• adjective Composed of two unlike parts; dual.
• adjective Accommodating or designed for two.
• adjective Characterized by duplicity; deceitful.
• adjective Botany Having many more than the usual number of petals, usually in a crowded or an overlapping arrangement.
• noun Something increased twofold.
• noun One that closely resembles another; a duplicate.
• noun Something having two identifiable or prominent parts or members.
• noun Something capable of carrying, moving, or holding two people or things, as a mattress.
• noun An actor's understudy.
• noun An actor who takes the place of another actor in scenes requiring special skills or preparations.
• noun An apparition; a wraith.
• noun A sharp turn in a direction of movement; a reversal.
• noun A sharp, often devious change in position or argument; a shift.
• noun Sports A form of a game, such as tennis or handball, having two players on each side.
• noun Baseball A hit enabling the batter to reach second base.
• noun A bid in bridge indicating strength to one's partner; a request for a bid.
• noun A bid doubling one's opponent's bid in bridge, thus increasing the penalty for failure to fulfill the contract.
• noun A hand justifying such a bid.
• intransitive verb To make twice as great.
• intransitive verb To be twice as much as.
• intransitive verb To fold in two.
• intransitive verb To clench (one's fist).
• intransitive verb To duplicate; repeat.
• intransitive verb To turn (an enemy spy) into a double agent.
• intransitive verb To cause the scoring of (a run) by hitting a double.
• intransitive verb To advance or score (a runner) by hitting a double.
• intransitive verb To put out (a runner) as the second part of a double play.
• intransitive verb Games To challenge (an opponent's bid) with a double in bridge.
• intransitive verb Music To duplicate (another part or voice) an octave higher or lower or in unison.
• intransitive verb Nautical To sail around.
• intransitive verb To be increased twofold.
• intransitive verb To turn sharply or all the way around; reverse one's course.
• intransitive verb To serve in an additional capacity.
• intransitive verb To replace an actor in the actor's absence or in a certain scene.
• intransitive verb Baseball To hit a double.
• intransitive verb Games To announce a double in bridge.
• adverb To twice the amount or extent; doubly.
• adverb Two together; in pairs.
• adverb In two.
• idiom (on/at) Immediately.
• idiom (on/at) In double time.