Protoctista Pro·toc·tis·ta (prō'tək-tĭs'tə) n. A taxonomic kingdom consisting of unicellular protists and their descendant multicellular organisms, considered as a separate taxonomic kingdom in most modern classification systems.
protoctista in Culture
Protoctista [(pruh-tohk-tis-ta)]
The kingdom of organisms, mostly single celled, whose cells contain a nucleus. The amoeba is a member of this kingdom.