Definitions
1.NounAny of the eukaryotic, usually unicellular organisms—including protozoans, slime molds and some algae—historically grouped into the kingdom Protista (or Protoctista), now distributed over several clades; any eukaryote that is not a plant, animal or fungus.
2.NounAny single-celled eukaryote, prokaryote or sponge .mw-parser-output .defdate{font-size:smaller}.
3.NounAny single-celled eukaryote or prokaryote .
4.NounAny single-celled eukaryote .