Any of various eukaryotic organisms belonging to the kingdom Protoctista in some classification systems. Protoctists include unicellular and multicellular organisms that are not fungi, plants, or animals. They are usually now referred to as protists.
[From New Latin Prōtoctista, kingdom name : Greek prōto-, proto- + Greek ktistos, produced, created (from ktizein, to create, establish; see tkei- in the Appendix of Indo-European roots).]
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