ADJ.
circular
VERB + OPERCULUM
called, lifted
PREP.
from
noun
A covering flap in animals, such as a gill cover.
Hyoliths […] have a small, conical calcium carbonate shell, with a lid called an operculum.
The lidlike portion of a moss sporangium or of a fruit that detaches to allow the dispersal of spores or seeds.
A gum flap covering (part of) a partially erupted tooth, usually a wisdom tooth.
A structure which serves as a cover or lid.
I lifted the circular operculum from its place and laid it carefully on the bale.
One of several flaps of cerebral cortex covering the insula.