Protozoa are very small organisms which often live inside larger animals.
[technical]
protozoan in British English
(ˌprəʊtəˈzəʊən)
noun
1. Also called: protozoon (ˌprəʊtəˈzəʊɒn)Word forms: plural-zoa (-ˈzəʊə)
any 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
2.
of or relating to protozoans
Word origin
C19: via New Latin from Greek proto- + zōion animal
protozoan in American English
(ˌproʊtəˈzoʊən)
noun
1. Word forms: pluralˌprotoˈzoans or ˌprotoˈzoa (ˌproʊtəˈzoʊə)
any of a subkingdom (Protozoa) of microscopic animals made up of a single cell or a group of more or less identical cells and living in water or as parasites, including ciliates, flagellates, rhizopods, and sporozoans
: sometimes ˌprotoˈzoˌon (ˌproʊtoʊzoʊˌɑn; ˌproʊtəˈzoʊˌɑn)Word forms: pluralˌprotoˈzoons or ˌprotoˈzoa (ˌprotəˈzoʊə)
adjective
2.
of the protozoans
: often ˌprotoˈzoic (ˌproʊtoʊzoʊɪk; ˌproʊtəˈzoʊɪk) or ˌprotoˈzoal
Word origin
< ModL Protozoa, name of the phylum (see proto- & -zoa) + -an