noun
bacillus
buh-SIL-us/bəˈsɪləs/
A rod-shaped bacterium.
Under the microscope, the bacillus appears as a tiny rod.
Etymology
Latin bacillus meant a “little staff” or “wand.” Its application to a bacterium describes the organism’s rod-like shape on a microscopic scale.
In context
… influenza was caused by a rod-shaped bacterium called Pfeiffer's bacillus.
More examples
- Several bacilli were visible in the stained sample.
- The student distinguished the bacillus from a round bacterium.
- The culture contained clusters of rod-shaped bacilli.
Forms
bacillus · bacilli
Similar words
- bacterium
- Is the general term regardless of the organism's shape.
- coccus
- Specifically names a spherical rather than rod-shaped bacterium.