Main Entry:

ba·cil·lus

Pronunciation:

\bə-ˈsi-ləs\

Function:

noun

Inflected Form(s):

plural ba·cil·li \-ˌlī also -lē\

Etymology:

New Latin, from Medieval Latin, small staff, rod, diminutive of Latin baculus staff, alteration of baculum

Date:

circa 1879

1: any of a genus (Bacillus) of rod-shaped gram-positive usually aerobic bacteria producing endospores and including many saprophytes and some parasites (as B. anthracis of anthrax) ; broadly : a straight rod-shaped bacterium2: bacterium ; especially : a disease-producing bacterium