# bacillus

/bəˈsɪɫəs/ (US) · /bˈæsɪləs/ (UK) · CEFR C1 · Noun

Source: https://englishreference.com/word/bacillus
Updated: 2026-05-30

## Definition

a type of bacteria that is shaped like a small rod. These tiny organisms are found almost everywhere in nature, including in soil and water.

For teachers: a rod-shaped bacterium, typically belonging to the genus Bacillus. These prokaryotes are often motile and can form endospores, allowing them to survive in harsh environments.

## Examples

- The scientist identified a bacillus in the soil sample.
- Certain species of bacillus are used in the production of antibiotics and other industrial enzymes.
- While many bacillus strains are harmless or even beneficial to the ecosystem, some can cause serious infections in humans if they enter the bloodstream through a wound.

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