monera, n. pl. [NL., fr. Gr. mo`nos single.].
The lowest division of rhizopods, including those which resemble the amœbas, but are destitute of a nucleus. [1913 Webster]
One of the five kingdoms of living organisms in the five-kingdom classification, consisting of microscopic usually monocellular prokaryotic organisms that mostly reproduce by asexual fission, sporulation, or budding; it includes the bacteria and cyanophytes (blue-green algae), as well as certain primitive pathogenic microbes, such as the Rickettsias. [PJC]