noun
- a small lid or cover-like structure, especially the bony plate covering the gills of a fish
Usage: biology; ichthyology
Examples
- The fish's opercule flapped open and closed as it breathed underwater.
- Marine biologists examined the opercule to identify the species.
- Each gill is protected by a bony opercule on the side of the fish's head.
- The opercule is a key adaptation that allows fish to regulate water flow over their gills.