/proh'teuh zoh"euhn/ , n. , pl. protozoans , ( esp. collectively ) protozoa /-zoh"euh/ , adj. Biol.
n.
1. any of a diverse group of eukaryotes, of the kingdom Protista, that are primarily unicellular, existing singly or aggregating into colonies, are usually nonphotosynthetic, and are often classified further into phyla according to their capacity for and means of motility, as by pseudopods, flagella, or cilia.
adj.
2. of, pertaining to, or characteristic of a protozoan.
[ 1860-65; PROTOZO(A) + -AN ]