Noun

• S: (n) double, two-base hit, two-bagger, two-baser (a base hit on which the batter stops safely at second base) "he hit a double to deep centerfield"
• S: (n) double, stunt man, stunt woman (a stand-in for movie stars to perform dangerous stunts) "his first job in Hollywood was as a double for Clark Gable"
• S: (n) double, image, look-alike (someone who closely resembles a famous person (especially an actor)) "he could be Gingrich's double"; "she's the very image of her mother"
• S: (n) double (a quantity that is twice as great as another) "36 is the double of 18"
• S: (n) doubling, double (raising the stakes in a card game by a factor of 2) "I decided his double was a bluff"

Verb

• S: (v) double, duplicate (increase twofold) "The population doubled within 50 years"
• S: (v) double (hit a two-base hit)
• S: (v) double over, double, double up (bend over or curl up, usually with laughter or pain) "He doubled and vomited violently"
• S: (v) double (do double duty; serve two purposes or have two functions) "She doubles as his wife and secretary"
• S: (v) double (bridge: make a demand for (a card or suit))
• S: (v) duplicate, reduplicate, double, repeat, replicate (make or do or perform again) "He could never replicate his brilliant performance of the magic trick"

Adjective

• S: (adj) double, dual, twofold, two-fold, treble, threefold, three-fold (having more than one decidedly dissimilar aspects or qualities) "a double (or dual) role for an actor"; "the office of a clergyman is twofold; public preaching and private influence"- R.W.Emerson; "every episode has its double and treble meaning"-Frederick Harrison
• S: (adj) double, dual, duple (consisting of or involving two parts or components usually in pairs) "an egg with a double yolk"; "a double (binary) star"; "double doors"; "dual controls for pilot and copilot"; "duple (or double) time consists of two (or a multiple of two) beats to a measure"
• S: (adj) double, doubled, twofold, two-fold (twice as great or many) "ate a double portion"; "the dose is doubled"; "a twofold increase"
• S: (adj) double (used of flowers having more than the usual number of petals in crowded or overlapping arrangements) "double chrysanthemums have many rows of petals and are usually spherical or hemispherical"
• S: (adj) bivalent, double (used of homologous chromosomes associated in pairs in synapsis)
• S: (adj) double (large enough for two) "a double bed"; "a double room"
• S: (adj) double, forked (having two meanings with intent to deceive) "a sly double meaning"; "spoke with forked tongue"

Adverb

• S: (adv) double (downward and forward) "he was bent double with pain"
• S: (adv) double (two together) "some people sleep better double"
• S: (adv) doubly, double, twice (to double the degree) "she was doubly rewarded"; "his eyes were double bright"