peri·din·i·um
| \ ˌperəˈdinēəm \
Definition of peridinium
1
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
2
plural peridiniums\
-ēəmz
\ or peridinia\
-ēə
\
: any flagellate of the genus Peridinium
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