Any of a large group of one-celled organisms that lack a cell nucleus, reproduce by fission or by forming spores, and in some cases cause disease. They are the most abundant lifeforms on Earth, and are found in all living things and in all of the Earth's environments. Bacteria usually live off other organisms. Bacteria make up most of the kingdom of prokaryotes (Monera or Prokaryota), with one group (the archaea) sometimes classified as a separate kingdom.
(US) A type, species, or strain of bacterium
Find another word for bacterium. In this page you can discover 18 synonyms, antonyms, idiomatic expressions, and related words for bacterium, like: archaeon prokaryote, bacteria, micro-organism, microbe, microorganism, toxin, pathogen, parasite, organism, bacterial and fungus.