opercular

/oʊˈpɜrkjələr/
adjective
  1. Relating to or serving as a lid or cover, especially a protective flap or plate in animals or plants.
    • The opercular bones in fish help protect the delicate gill tissues.
    • Some snails have an opercular structure that seals the shell opening.
    • The opercular flap covers the gills of most bony fish.
noun
  1. A lid-like structure or covering part, such as the gill cover of a fish or the lid of a moss capsule.
    • The opercular of the moss opened to release spores.
    • Biologists studied the opercular to understand how the fish breathes.
    • The opercular of the fish was bright orange and easy to see.
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