What does amoeboid mean?
Amoeboid is an adjective describing something that resembles an amoeba — most often a cell or organism that moves and changes shape the way an amoeba does, by extending temporary arm-like projections called pseudopodia. The term belongs primarily to biology, where it is routinely applied to crawling cells such as white blood cells, certain parasites, and slime moulds. By extension, it can describe anything with a soft, shifting, ill-defined outline, giving it occasional figurative use outside science. The word derives from the Greek amoibē, meaning 'change' or 'alternation', the same root that produced 'amoeba' itself. Precise and evocative at once, amoeboid conveys both a specific mode of locomotion and a broader impression of fluid, restless formlessness, making it valuable wherever shape-shifting movement needs a name.
adjectiveResembling an amoeba, especially in being able to change shape or in moving by means of pseudopodia (temporary projections of the cell). Used chiefly in biology to describe cells or organisms that move or behave like an amoeba.
- Describing a cell or organism that moves or changes shape like an amoeba, typically by extending pseudopodia.
- More generally, describing anything resembling an amoeba in form or character.
"White blood cells move through tissue in an amoeboid fashion, extending their bodies around obstacles."
"The parasite spreads through the bloodstream in an amoeboid manner, squeezing between the vessel walls."
"The sculpture had an oddly amoeboid quality, its edges seeming to flow and shift as you walked past."
Your own immune cells are amoeboid — they crawl through your body by oozing into new shapes, just like the pond-dweller that gave the word its name.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of amoeboid
Amoeboid comes from the Greek noun amoibē, meaning 'change' or 'exchange', which also underlies the biological term amoeba coined in the 19th century when these shape-shifting microorganisms were first described. The adjective was formed by adding the suffix -oid ('resembling'), following the standard Greek-derived pattern seen in words like android and humanoid. Its cognates therefore include amoeba, amoebic, and related medical terms such as amoebiasis.
How amoeboid is actually used
A technical term used mainly in biology and medicine, though it occasionally appears in general writing to describe something shapeless or ever-changing. It is almost always adjectival; there is no common noun or verb form derived from it.
Easily confused with amoeboid
An amoeba is the single-celled organism itself (a noun), while amoeboid describes anything that resembles an amoeba in form or movement.
Amorphous means lacking any definite shape at all, whereas amoeboid specifically suggests the shifting, flowing form characteristic of an amoeba.