protozoan Zoology [ ˌprəʊtə'zəʊən ]
■ noun a single-celled microscopic animal of a group of phyla of the kingdom Protista, which includes amoebas, flagellates, ciliates, and sporozoans.
■ adjective relating to protozoans.
Derivatives
protozoal adjective
protozoon noun
Origin
from mod. L. Protozoa (former phylum name), from proto- + Gk zōion 'animal'.