Nummulite

Part of speech: noun

Definitions

1. A microscopic fossil of a marine protozoan with a calcareous shell, common in Eocene and Paleocene limestone formations, characterized by its coin-like, disc-shaped structure
2. An ancient single-celled organism fossilized in sedimentary rocks, notable for its rounded, layered shells often resembling small coins, primarily found in geological strata dating to the early Tertiary period
3. The preserved remains of a tiny marine shelled protozoan whose circular, segmented shells contribute significantly to certain limestone deposits formed during the early Cenozoic era

Etymology: Nummulites are fossils of single-celled marine organisms, and their name comes from the Latin "nummulus," meaning "little coin." The shells are flat and disc-shaped, often no bigger than a coin, so early observers saw them as petrified money. Many of the limestone blocks used to build the pyramids of Egypt are packed with them. The word reached English through French "nummulite," which was formed from the same Latin root. Naturalists then made "Nummulites" into a scientific genus name, and the English noun came from that genus. The ending "-ite" is the standard suffix for fossils and minerals, so the word is a Latin diminutive for coin plus a suffix that marks it as a fossil.

Synonyms: foraminifera, marine protozoan, fossil foraminifera, carbonate fossil