catflap.org Online Dictionary Query

  twin
     n.
     1 Either of two people (or, less commonly, animals) who shared the
  same uterus at the same time; one who was born at the same birth as a
  sibling.
     2 Either of two similar or closely related objects, entities etc.
     3 A room in a hotel, guesthouse, etc. with two beds; a twin room.
     4 (lb en US) A twin size mattress or a bed designed for such a
  mattress.
     5 (lb en aviation) A two-engine aircraft.
     6 (lb en crystallography) A twin crystal.
     vb.
     1 (lb en transitive obsolete outside Scotland) To separate, divide.
     2 (lb en intransitive obsolete outside Scotland) To split, part; to
  go away, depart.
     3 (lb en usually in the passive) To join, unite; to form links
  between (now especially of two places in different countries); to pair
  with.
     a.
     1 double; dual; occurring as a matching pair.
     2 Forming a pair of twins.
     Old English a.
     (alternative form of ang twinn)

  Twin
     n.
     (lb en baseball) A player who plays for the
  https://en.wikipedia.org/wiki/Minnesota%20Twins.