The Collaborative International Dictionary of English v.0.48:

Amoeba \A*moe"ba\, Amoeba \A*m[oe]"ba\, n.; pl. L.
   Am[oe]b[ae]; E. Am[oe]bas. [NL., fr. Gr. ? change.]
   (Zool.)
   A rhizopod common in fresh water, capable of undergoing many
   changes of form at will. Same as ameba. See Rhizopoda.
   [1913 Webster]

WordNet (r) 3.0 (2006):

amoeba
    n 1: naked freshwater or marine or parasitic protozoa that form
         temporary pseudopods for feeding and locomotion [syn:
         ameba, amoeba]

Moby Thesaurus II by Grady Ward, 1.0:

56 Moby Thesaurus words for "amoeba":
   Euglena, adenovirus, aerobe, aerobic bacteria, anaerobe,
   anaerobic bacteria, animalcule, bacillus, bacteria, bacterium, bug,
   coccus, colon bacillus, diatom, disease-producing microorganism,
   dyad, echovirus, enterovirus, filterable virus, flagellate, fungus,
   germ, gram-negative bacteria, gram-positive bacteria, microbe,
   microorganism, microspore, microzoa, mold, monad, nematode,
   nonfilterable virus, paramecium, pathogen, picornavirus, protozoa,
   protozoon, reovirus, rhinovirus, rickettsia, salmonella,
   saprophyte, spirillum, spirochete, spore, sporozoon,
   staphylococcus, streptococcus, tetrad, triad, trypanosome, vibrio,
   virus, volvox, vorticellum, zoospore



The Free On-line Dictionary of Computing (30 December 2018):

Amoeba

   1.  A distributed operating system
   developed by Andrew S. Tanenbaum and others of Vrije
   Universiteit, Amsterdam.  Amoeba is only available under
   licence from the VUA, but is free of charge and includes all
   source, binaries and documentation.

   (http://am.cs.vu.nl/).

   [Features?]

   2.  A derogatory term for Commodore's
   Amiga personal computer.

   [Jargon File]

   (1997-05-07)