monera

‖n. pl. [ NL., fr. Gr. mo`nos single. ] (Zool.) The lowest division of rhizopods, including those which resemble the amoebas, but are destitute of a nucleus. [ archaic ] [ 1913 Webster ]

2. (Biol.) 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 ]