bacterium
Pluralbacteria
- 1A single-celled organism that has a cell wall but lacks a nucleus and other internal compartments.
Under the microscope, a single bacterium looked like a tiny rod.
Certain gut bacteria help humans digest fiber.
Similarmicrobe
Note
A Latin singular with a Greek picture inside it: the word comes through New Latin from baktḗrion, "small staff," so the name itself imagines a little rod. Its plural is bacteria, which means careful writing keeps one bacterium and many bacteria apart. Writing "a bacteria" mixes the two numbers, and the anglicized bacteriums is nonstandard. In microbiology, the singular is the precise choice when the point is one organism.
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Origin
From New Latin bactērium, from the Ancient Greek βακτήριον (baktḗrion, "small staff"), derived from βακτηρία (baktēría).