peridinium

noun

peri·din·i·um

ˌperəˈdinēəm

capitalized : the type genus of Peridiniidae comprising marine and freshwater dinoflagellates that are typically subspherical to ovoid in outline and that sometimes have the test prolonged into short horns compare ceratium

plural peridiniums

-ēəmz

or peridinia

-ēə

: any flagellate of the genus Peridinium

Word History

Etymology

borrowed from New Latin, borrowed from Greek peridīn-, base of peridīneîn "to whirl, spin around" (from peri- peri- + dīneîn "to whirl, spin about") + New Latin -ium -ium