PROTOZOAN

[pro.to.zo.an] n [NL Protozoa, fr. prot- + -zoa] (ca. 1864): any of a phylum or subkingdom (Protozoa) of chiefly motile and heterotrophic unicellular protists (as amoebas, trypanosomes, sporozoans, and paramecia) that are represented in almost every kind of habitat and include some pathogenic parasites of humans and domestic animals -- protozoan adj