protist

n. single-celled organism from the kingdom Protista

Protists , Greek protiston -a meaning the (most) first of all ones, are a diverse group of organisms, comprising those eukaryotes that cannot be classified in any of the other kingdoms as fungi, animals, or plants. They are usually treated as the kingdom Protista or Protoctista. Protoctists (or protists) are a paraphyletic grade, rather than a natural, (monophyletic) group, and so do not have much in common besides a relatively simple organization -- either they are unicellular, or they are multicellular without highly specialized tissues. The term protista was coined by Ernst Haeckel in 1866.
See more at Wikipedia.org...

Noun
1. free-living or colonial organisms with diverse nutritional and reproductive modes
(synonym) protistan
(hypernym) microorganism
(member-holonym) Protista, division Protista

n. protist, single-celled organism from the kingdom Protista

(n.)
One of the Protista.