[ad_1] plural noun, singular ar·chae·bac·te·ri·um [ahr-kee-bak-teer-ee-uh m] /ˌɑr ki bækˈtɪər i əm/.
- a group of microorganisms, including the methanogens and certain halophiles and thermoacidophiles, that have RNA sequences, coenzymes, and a cell wall composition that are different from all other organisms: considered to be an ancient form of life that evolved separately from the bacteria and blue-green algae and sometimes classified as a kingdom.
pl n
- (formerly) a group of microorganisms now regarded as members of the ArchaeaSee archaean
plural of archaebacterium (1977), from archaeo- + bacterium (see bacteria).
Plural archaebacteria
- A former name for archaeon.