- Singlecelled organism - Unicellular organism - An ultimate atom, or simple, unextended point; something
ultimate and indivisible. - The elementary and indestructible units which were conceived
of as endowed with the power to produce all the changes they undergo,
and thus determine all physical and spiritual phenomena. - One of the smallest flangellate Infusoria; esp., the species
of the genus Monas, and allied genera. - A simple, minute organism; a primary cell, germ, or plastid. - An atom or radical whose valence is one, or which can
combine with, be replaced by, or exchanged for, one atom of hydrogen.