- Noun. (plural of, bacterium) .
- Noun. (US) A type, species, or strain of bacterium.
- Noun. (US, proscribed) (alternative form of, bacterium) .
- Noun. (pejorative, slang) A derisive term for a lowlife or a slob (could be treated as plural or singular).
- Noun. (dated, medicine) An oval bacterium, as distinguished from a spherical coccus or rod-shaped bacillus.