Source : Webster's Revised Unabridged Dictionary (1913)

Laocoon \La*oc"o*["o]n\, n. [L., fr. Gr. ? ]
   1. (Class. Myth.) A priest of Apollo, during the Trojan war.
      (See 2.)

   2. (Sculp.) A marble group in the Vatican at Rome,
      representing the priest Laoco["o]n, with his sons,
      infolded in the coils of two serpents, as described by
      Virgil.

Source : WordNet®

Laocoon
     n : (Greek mythology) the priest of Apollo who warned the
         Trojans to beware of Greeks bearing gifts when they
         wanted to accept the Trojan Horse; a god who favored the
         Greeks (Poseidon or Athena) sent snakes who coiled around
         Laocoon and his two twin sons killing them