any of a diverse group of eukaryotes, of the kingdom Protista, that are primarily unicellular, existing singly or aggregating into colonies, are usually nonphotosynthetic, and are often classified further into phyla according to their capacity for and means of motility, as by pseudopods, flagella, or cilia.
of, relating to, or characteristic of a protozoan.
Also called: protozoon (ˌprəʊtəˈzəʊɒn) plural-zoaany of various minute unicellular organisms formerly regarded as invertebrates of the phylum Protozoa but now usually classified in certain phyla of protoctists. Protozoans include flagellates, ciliates, sporozoans, amoebas, and foraminifers
adjective Also: protozoic
of or relating to protozoans
Word Origin for protozoan
C19: via New Latin from Greek proto- + zoion animal
1828, from Modern Latin Protozoa, coined 1818 by German zoologist Georg August Goldfuss (1782-1848) from Greek protos "first" (see proto-) + zoia, plural of zoion "animal" (see zoo). Originally including sponges and corals; current sense is from 1845. Related: Protozoon (aingular); Protozoan.
Any of a large group of one-celled organisms (called protists) that live in water or as parasites. Many protozoans move about by means of appendages known as cilia or flagella. Protozoans include the amoebas, flagellates, foraminiferans, and ciliates. Their traditional classification as the subkingdom Protozoa is still used for convenience, but it is now known that protozoans represent several evolutionarily distinct groups. See more at protist.