bacteria

/bækˈtɪəɹ.ɪ.ə/noun

A particular kind, species, or strain of these tiny single-celled organisms.

Example sentence

“Certain bacteria in yogurt aid digestion.”

Grammatically plural: careful writing says "bacteria are", with "bacterium" as the singular. Informal English treats it as singular anyway.

Related words

germA tiny living thing, such as a bacterium or virus, that can cause illness.virusAn illness caused by an infectious viral agent.diseaseA condition that makes a person, animal, or plant unwell or stops it working properly, unlike an injury, which usually happens in an instant.outbreakThe sudden start or rapid spread of something unpleasant, such as a disease.chronicLasting for a long time or coming back again and again, used of problems or illnesses.pandemicA disease that spreads across many countries and infects a very large share of the population.