amoeba (n.) Look up amoeba at Dictionary.com
type of microscopic protozoa, 1855, from Modern Latin Amoeba, genus name (1841 in English, said to have been used 1830 by German naturalist Christian Ehrenberg), from Greek amoibe "change, alteration; exchange," which is related to ameibein "to change, exchange," from PIE *e-meigw-, extended form of root *mei- (1) "to change, go, move" (see mutable). So called for its constantly changing shape. An earlier popular name for it was proteus (1660s). Related: Amoebic; amoebiform; amoeboid.