microbe

Synonym discussion

Sense: noun/1

Microbe, microorganism, germ, bacterium, and virus all refer to tiny life forms, but they differ in scope and formality. 'Microorganism' is the broadest and most technical term, covering all microscopic life including bacteria, fungi, and protozoa. 'Microbe' is a slightly less technical synonym for 'microorganism', common in health and science writing. 'Germ' is informal and focuses on disease-causing organisms—you 'catch germs', but you would not say 'gut germs' in formal writing. 'Bacterium' names a specific kingdom of single-celled organisms; all bacteria are microbes, but not all microbes are bacteria. 'Virus' is distinct: viruses are not cells and cannot reproduce on their own, so technically they are not microbes. For a general discussion of tiny organisms in soil or the human body, 'microbe' and 'microorganism' are appropriate; for casual talk about illness, 'germ' fits better.

Common collocations