Other forms: bacteria
A bacterium is one single-celled living thing without a nucleus. A single bacterium, an airborne bacterium, identify the bacterium.
The plural is bacteria, and using it as a singular is the commonest error with the word. They outnumber human cells in a human body, and most of them are harmless or necessary — the ones that cause disease are a small minority of an enormous group.
1nounbacteriumOne single-celled living thing without a nucleus.
“Scientists identified the bacterium responsible for the food poisoning outbreak.”
bacterium is an organism.
Greek bakterion means a little staff, from the rod shape of the first ones seen under a microscope.
New Latin
bactērium
English, today
bacterium
Borrowed from New Latin bactērium. From New Latin bactērium, from Ancient Greek βακτήριον (“small staff”), from βακτηρία.
Etymology from Wiktionary, CC BY-SA