[ahr-kee-bak-teer-ee-uh] 
[-teer-ee-uh
m] . | 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. |
| archaebacterium (är'kē-bāk-tîr'ē-əm) Pronunciation Key
Plural archaebacteria See archaeon. |