dinoflagellate of genus Ceratium
A type of marine plankton; the name refers to the horn-like shape. Usually written in katakana in biological contexts.
Tsunomo is a type of dinoflagellate widely distributed in seawater.
I observed the characteristic horn-shaped shell of Tsunomo under a microscope.
Kanji spelling is rare; the word is usually written in kana.
Hiragana spelling is also used.
From 角 (つの, 'horn') + 藻 (も, 'algae'), referring to the horn-like shape of the organism.