'Epiphragm' definitions:

Definition of 'Epiphragm'

From: GCIDE

Epiphragm \Ep"i*phragm\, n. [Gr. ? a covering, lid, fr. ? to block up.] (Zo["o]l.) A membranaceous or calcareous septum with which some mollusks close the aperture of the shell during the time of hibernation, or estivation. [1913 Webster]