Source : Webster's Revised Unabridged Dictionary (1913)

Amoeba \A*m[oe]"ba\, n.; pl. L. {Am[oe]b[ae]}; E. {Am[oe]bas}.
   [NL., fr. Gr. ? change.] (Zo["o]l.)
   A rhizopod. common in fresh water, capable of undergoing many
   changes of form at will. See {Rhizopoda}.

Source : WordNet®

amoeba
     n : naked freshwater or marine or parasitic protozoa that form
         temporary pseudopods for feeding and locomotion [syn: {ameba}]
     [also: {amoebae} (pl)]

amoebae
     See {amoeba}