operculum

oper·cu·lum

noun \ō-ˈpər-kyə-ləm\

plural oper·cu·la\-lə\ also oper·cu·lums

Definition of OPERCULUM

1

: a body process or part that suggests a lid: as a : a horny or shelly plate on the posterior dorsal surface of the foot in many gastropod mollusks that closes the shell when the animal is retracted b : the covering of the gills of a fish — see fish illustration

2

: a lid or covering flap (as of a moss capsule)

Origin of OPERCULUM

New Latin, from Latin, cover, from operire to shut, cover

First Known Use: 1681