What does ameba mean?
An ameba is a single-celled microorganism belonging to a group of protozoans characterized by their ability to move and feed using pseudopodia — temporary, flowing extensions of the cell's cytoplasm. The term is an accepted American variant spelling of the more widely used "amoeba," which derives from the Greek word "amoibē," meaning change or alteration, a fitting origin for organisms famous for their ever-shifting shape. In scientific contexts, amebas are studied as model organisms for cell biology, while certain species, such as Entamoeba histolytica, are medically significant as causes of amebic dysentery. Beyond biology, the word occasionally appears figuratively to describe something formless, primitive, or constantly changing, such as an unstructured organization. Because "ameba" and "amoeba" name the same organism, readers should recognize both spellings, though "amoeba" predominates in modern scientific writing.
nounAmeba is a variant spelling of amoeba, referring to a single-celled microorganism of the phylum Amoebozoa that moves and feeds by means of temporary projections of its cytoplasm called pseudopodia.
- A single-celled organism that moves and feeds using pseudopodia.
- Loosely, any shapeless or constantly changing entity (figurative use).
"Under the microscope, the ameba extended a pseudopod and slowly engulfed its prey."
"The biology students observed a live ameba gliding across the slide."
"Critics dismissed the organization as an ameba, lacking any fixed structure or direction."
The regular English plural is "amebas." The Latinate plural "amebae" also appears, mirroring "amoebae."
"Several amebas were visible under low magnification."
The word comes straight from the Greek 'amoibē,' meaning 'change' — fitting for a creature whose entire body constantly reshapes itself.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of ameba
The word traces to the Greek "amoibē," meaning change or alternation, reflecting the organism's constantly shifting form. It was coined in the mid-19th century when early microscopists formalized the classification of these protists, with the naturalist Christian Gottfried Ehrenberg playing a key role in establishing the genus name. "Ameba" arose as an American simplified spelling of "amoeba," which had passed through New Latin from the Greek. The Greek root also underlies related biological terms such as "amebic" and "amebiasis."
Related word forms
How ameba is actually used
"Ameba" is primarily an American spelling variant; "amoeba" is more common in British English and in most scientific literature. The plural is correctly "amebas" or "amebae," though "amoebae" is often seen when the amoeba spelling is used.
Easily confused with ameba
Amoeba is the standard international and British spelling, while ameba is an accepted American variant of the same word.