Variant of operculum
- the bony covering protecting the gills of fishes: see fish,
- in many gastropods, the horny plate serving to close the shell when the animal is retracted
- the lid of spore cases in mosses
- the lid of a pitcher-shaped leaf
Origin: ModL from L, lid, diminutive from operire, to close, shut: for Indo-European bases see ob- and amp; aperture
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