[ bak'tɪərɪəm ]
■ noun ( plural bacteria -rɪə ) a member of a large group of unicellular microorganisms (prokaryotes) which have cell walls but lack an organized nucleus and other structures, and include numerous disease-causing forms.
Derivatives
bacterial adjective
bacterially adverb
Origin
C19: mod. L., from Gk baktērion , dimin. of baktēria 'rod, cane' (because the first ones to be discovered were rod-shaped).
Usage
Bacteria , the plural form of ~ , is sometimes mistakenly treated as a singular form.