PROTOZOAN

noun Etymology: New Latin Protozoa, from prot- + -zoa Date: circa 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, ~ adjective