Operculum

Rarity: Common

The most frequent rarity: most Wikipedia articles become Commons.

Rarity follows how well known the article is: its views on the French and English Wikipedia over a year, and the number of languages it exists in.

At a glance

Class

Notion

Domain

Science and technology

In collections

Nobody has pulled it yet.

What Wikipedia says

An operculum (Latin for 'cover, covering'; pl. opercula or operculums) is a corneous or calcareous anatomical structure like a trapdoor that exists in many (but not all) groups of sea snails and freshwater snails, and also in a few groups of land snails, including the Helicinidae, Cyclophoridae, Aciculidae, Maizaniidae and Pomatiidae.

Excerpt from the Wikipedia article “Operculum (gastropod)”, under the CC BY-SA 4.0 license. Read the article on Wikipedia

Image: Jan Delsing, Public domain, via Wikimedia Commons.