What is the meaning of doubles?

noun

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

verb

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