bacteria[plural noun]
microorganisms, bacilli, bugs 
(slang), germs, microbes, pathogens, viruses 
 [TahlilGaran] English Synonym Dictionary ▲
 bac‧te‧ri‧a /bækˈtɪəriə $ -ˈtɪr-/ 
 noun [plural] (
singular bacterium /-riəm/)
[
Date: 1800-1900; 
Language: Modern Latin; 
Origin: Greek bakterion 'stick, rod'; because of their shape]
 very small living things, some of which cause illness or disease ⇒ 
virus—bacterial adjective: 
 a bacterial infection
 a bacterial infection  [TahlilGaran] Dictionary of Contemporary English ▲