Dictionary.com
definitions

anaerobe

[an-uh-rohb, an-air-ohb]
noun
  1. an organism, especially a bacterium, that does not require air or free oxygen to live (opposed to aerobe).

Origin of anaerobe

First recorded in 1875–80; an-1 + aerobe
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for anaerobe

anaerobe

anaerobium (ˌænɛəˈrəʊbɪəm)

noun plural -obes or -obia (-ˈəʊbɪə)
  1. an organism that does not require oxygen for respirationCompare aerobe
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
anaerobe in Medicine

anaerobe

[ăn′ə-rōb′, ăn-âr′ōb′]
n.
  1. An organism that can live in the absence of atmospheric oxygen.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
anaerobe in Science

anaerobe

[ăn′ə-rōb′]
  1. An organism, such as a bacterium, that can or must live in the absence of oxygen. Compare aerobe.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.