Protractor

n.
  1. One who, or that which, protracts, or causes protraction.
  2. A mathematical instrument for laying down and measuring angles on paper, used in drawing or in plotting. It is of various forms, semicircular, rectangular, or circular.
  3. (Surg.) An instrument formerly used in extracting foreign or offensive matter from a wound.
  4. (Anat.) A muscle which extends an organ or part; -- opposed to retractor.
  5. An adjustable pattern used by tailors.