Definition of: bacterium

(bak·tir′ē·əm) noun plural ·te·ri·a (-tir′·ē·ə)
One of numerous widely distributed unicellular micro-organisms of the class Schizomycetes; autotrophic, heterotrophic, parasitic or saprophytic, they exhibit both plant and animal characteristics, and in their three varieties of bacillus, coccus, and spirillum range from the harmless and beneficial to the intensely virulent and lethal. [<NL <Gk. baktērion, dim. of baktron staff, stick]
—bac·te′ri·al adjective
—bac·te′ri·al·ly adverb
COCCUS FORMS OF BACTERIA
a. Staphylococcus.
b. Diplococcus.
c. Sarcina.
d. Streptococcus.
BACILLUS FORMS OF BACTERIA
e. Bacillus typhosus.
f. Bacillus sporagenes.
g. Bacillus subtilis.
h. Bacillus proteus.
SPIRILLUM FORMS OF BACTERIA
i. Spirillum undulam.
j. Species of spirochaete.
k. Thiospirillum.
l. Vibrio cholerae.