Nuclearia in the context of "Amoeba"

An amoeba or ameba /əˈmiːbə/ (pl.: amoebas or amebas (less commonly, amoebae or amebae /əˈmiːbi/)), often called an amoeboid, is a type of cell or unicellular organism with the ability to alter its shape, primarily by extending and retracting pseudopods. Amoebae do not form a single taxonomic group; instead, they are found in every major lineage of eukaryotic organisms. Amoeboid cells occur not only among the protozoa, but also in fungi, algae, and animals.

Microbiologists often use the terms "amoeboid" and "amoeba" interchangeably for any organism that exhibits amoeboid movement.