Word Study
anaerobes (root: anaerobe)
CIDE DICTIONARY
anaerobes, n. pl. [NL. anaerobia; an-not + aëro- + Gr. life.].
Anaërobic bacteria. They are called facultative anaërobes when able to live either in the presence or absence of free oxygen; obligate anaërobes , or obligatory anaërobes , when they thrive only in its absence. [Webster 1913 Suppl.]
For further exploring for "anaerobes" in Webster Dictionary Online