operculum

noun

oper·​cu·​lum ō-ˈpər-kyə-ləm 

plural opercula ō-ˈpər-kyə-lə  also operculums

1

: a body process or part that suggests a lid: such 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)

Examples of operculum in a Sentence

Recent Examples on the Web

The electroencephalographic laser-evoked potentials (LEPs) were modelled using six equivalent source dipoles located in the left and right fronto-opercular/anterior-insular cortex, left parietal operculum, left primary somatosensory cortex, medial parietal cortex and left medial temporal cortex. —Ncbi Rofl, Discover Magazine, 26 Sep. 2012

The finding of a seizure focus^ in the left frontal operculum, adjacent to the tumor, is consistent^ with the hypothesis that activation of this region by appetite^ triggered seizure activity that then propagated to the surrounding^ cortex and was manifest clinically as a motor seizure. —Neuroskeptic, Discover Magazine, 17 Mar. 2010

Scallops, for example, showcase a complex system of camouflage, with a colored shell on top and a white shell on the bottom; most gastropods are born with trapdoor-like devices called an operculum, which protect them from predators. —Susan Glaser, cleveland.com, 10 Jan. 2018

Word History

Etymology

borrowed from New Latin, going back to Latin, "cover, lid," from operīre "to shut, close, cover" (from op-, variant of ob- ob- + pre-Latin *-wer-je- "open or close," as specified by a prefix, going back to Indo-European *Hu̯er-) + -culum, instrumental suffix (going back to Indo-European *-tlom) — more at aperient

First Known Use

1681, in the meaning defined at sense 1

Medical Definition

operculum

noun

oper·​cu·​lum ō-ˈpər-kyə-ləm 

plural opercula -lə  also operculums

: any of several parts of the cerebrum bordering the sylvian fissure and concealing the insula