Definition from Wiktionary, the free dictionary
bacterium (plural bacteria)
- (microbiology) A single celled organism with no nucleus.
2013 July 20, “Welcome to the plastisphere”, The Economist, volume 408, number 8845:
- Plastics are energy-rich substances, which is why many of them burn so readily. Any organism that could unlock and use that energy would do well in the Anthropocene. Terrestrial bacteria and fungi which can manage this trick are already familiar to experts in the field.
- In most formal writing, bacterium is the singular form of the noun, and bacteria the plural form. This is in accord with the word's Latin etymology. However, in ordinary speech, some speakers use bacteria as a singular, with plural either bacteria or bacterias. This is usually considered incorrect.
- See also Wikisaurus:bacterium
single celled organism with no nucleus or organelles
Second declension neuter.