bacteria

UK: /bækˈtɪəriə/ US: /bækˈtɪriə/ ,(bak tēr′ē ə)

Inflections of 'bacteria' (npl): n: bacterium

WordReference Random House Learner's Dictionary of American English © 2025

bac•te•ri•a /bækˈtɪriə/   n. [plural], sing. bac•te•ri•um 

/bækˈtɪriəm/.  
1. Microbiology a group of microscopic, one-celled organisms, some of which are involved in infectious diseases, fermentation, and decay.

bac•te•ri•al, adj. 

WordReference Random House Unabridged Dictionary of American English © 2025

bac•te•ri•a  (bak tēr′ē ə), n.pl., sing. -te•ri•um 

(-tēr′ē əm). 
1. Microbiology 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.

• Greek bakté̄ria, plural of bakté̄rion; see bacterium
• Neo-Latin
• 1905–10

bac•te′ri•al, adj. 
bac•te′ri•al•ly, adv. 

Collins Concise English Dictionary © HarperCollins Publishers::

bacteria / bækˈtɪərɪə/ noun:plural ( -rium / -rɪəm/)

1. a very large group of microorganisms comprising one of the three domains of living organisms. They are prokaryotic, unicellular, and either free-living in soil or water or parasites of plants or animals
   See also prokaryote

Etymology: 19th Century: plural of New Latin bacterium, from Greek baktērion, literally: a little stick, from baktron rod, staff

bacˈterial adjective

bacˈterially adverb