Definitions

1. noun

A single cell that is the basic structural and functional unit of all bacteria, typically consisting of a cell wall and a single chromosome.

“The scientist studied the properties of the isolated bacterium under a microscope.”

2. noun

A microorganism, especially one that is pathogenic.

“The bacterium caused the patient’s severe case of food poisoning.”

3. noun

A type of microscopic organism, especially one that is used in research or industry.

“The scientist worked with a variety of bacterium species in her laboratory.”