a phylum or grouping of phyla which comprises the single-celled microscopic animals, which include amoebas, flagellates, ciliates, sporozoans, and many other forms. They are now usually treated as a number of phyla belonging to the kingdom Protista.
(protozoa) organisms of the Protozoa group.
modern Latin (plural), from proto- 'first' + Greek zōion 'animal'
Protozoa in other Oxford dictionaries
Definition of Protozoa in the US English dictionary