dinoflagellate
Concise Oxford English Dictionary © 2008 Oxford University Press:
dinoflagellate /ˌdʌɪnə(ʊ)ˈfladʒəleɪt/
▶noun a single-celled aquatic organism with two flagella, occurring in large numbers in marine plankton. [Division Dinophyta.]
– origin C19 (as adj.): from mod. L. Dinoflagellata, from Gk dinos ‘whirling’ + L. flagellum (see flagellum).
'dinoflagellate' also found in these Oxford entries:

