archaea 的定义
singular ar·chae·on [ahr-kee-on]. /ˈɑr kiˌɒn/. Microbiology.
- 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 classified by many biologists as constituting the domain Archaea.