'Metastome' definitions:

Definition of 'Metastome'

From: GCIDE

Metastoma \Me*tas"to*ma\, Metastome \Met"a*stome\, n. [NL. metastoma, from Gr. meta` behind + sto`ma mouth.] (Zool.) A median elevation behind the mouth in the arthropods. [1913 Webster]