[bak-teer-ee-uh
m] 
| sing. of bacteria. |
rion, dim. of baktēría staff; akin to báktron stick, L baculum, bacillum [bak-teer-ee-uh] [-teer-ee-uhm] . | ubiquitous one-celled organisms, spherical, spiral, or rod-shaped and appearing singly or in chains, comprising the Schizomycota, a phylum of the kingdom Monera (in some classification systems the plant class Schizomycetes), various species of which are involved in fermentation, putrefaction, infectious diseases, or nitrogen fixation. |
| bac·te·ri·um (bāk-tîr'ē-əm) n. pl. bac·te·ri·a (-tîr'ē-ə) Any of the unicellular prokaryotic microorganisms of the class Schizomycetes, which vary in terms of morphology, oxygen and nutritional requirements, and motility, and may be free-living, saprophytic, or pathogenic in plants or animals. [New Latin bactērium, from Greek baktērion, diminutive of baktron, rod; see bak- in Indo-European roots.] |
sing. bacterium
Microorganisms made up of a single cell that has no distinct nucleus. Bacteria reproduce by fission or by forming spores.
Note: Some bacteria are beneficial to humans (for example, those that live in the stomach and aid digestion), and some are harmful (for example, those that cause disease).
bacterium bac·te·ri·um (bāk-tēr'ē-əm)
n. pl. bac·te·ri·a (-tēr'ē-ə)
Any of the unicellular, prokaryotic microorganisms of the class Schizomycetes, which vary in terms of morphology, oxygen and nutritional requirements, and motility, and may be free-living, saprophytic, or pathogenic, the latter causing disease in plants or animals.
