D defs.my
Entry 1 sense Webster, 1913

butene

· IPA
01 n. any of three isomeric singly unsaturated hydrocarbons C4H8; all are used in making synthetic rubbers; -- called also butylene.
  1. 1.
    any of three isomeric singly unsaturated hydrocarbons C4H8; all are used in making synthetic rubbers; -- called also butylene. Also: butylene