[ ahr-kee-bak-teer-ee-uh ]
/ ˌɑr ki bækˈtɪər i ə /

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.
Also ar·chae·o·bac·te·ri·a [ahr-kee-oh-bak-teer-ee-uh] /ˌɑr ki oʊ bækˈtɪər i ə/.

Origin of archaebacteria

1977; < New Latin, equivalent to archae-, irregular for archaeo- archaeo- (perhaps an erroneous Latinizing of Greek arche- arche-) + bacteria bacteria Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for archaebacteria


/ (ˌɑːkɪbækˈtɪərɪə) /

pl n

(formerly) a group of microorganisms now regarded as members of the ArchaeaSee archaean

Word Origin for archaebacteria

from archaeo- + bacteria
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Science definitions for archaebacteria


[ är′kē-băk-tîrē-əm ]

Plural archaebacteria

A former name for archaeon.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.