[ahr-kee-bak-teer-ee-uh m] /ˌɑr ki bækˈtɪər i əm/ (Show IPA)
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.
[ahr-kee-oh-bak-teer-ee-uh] /ˌɑr ki oʊ bækˈtɪər i ə/ (Show IPA).
Origin of archaebacteria
1977; < New Latin, equivalent to archae-, irregular for archaeo-archaeo- (perhaps an erroneous Latinizing of Greekarche-arche-) + bacteriabacteria