noun
bacillus
ba-SIL-uhs
Bacillus (noun) means a member of the bacterial genus Bacillus, made up of organisms shaped like short rods that form spores, some of which are capable of causing illness. Example: “The lab identified the bacillus responsible for the outbreak.”
noun
1
technical A member of the bacterial genus Bacillus, made up of organisms shaped like short rods that form spores, some of which are capable of causing illness.
"The lab identified the bacillus responsible for the outbreak."
"Bacillus anthracis is the bacillus that causes anthrax."
"Some species of bacillus are used to make antibiotics."
2
technical Any rod-shaped bacterium.
"Under the microscope, the sample showed several rod-shaped bacilli."
"Not every bacillus belongs to the genus Bacillus."
How to use bacillus
Learner’s notesIn plain EnglishA bacillus is a rod-shaped bacterium, and some kinds can make people ill.
When to use it
This is a technical term used mainly in microbiology and medicine.
Common pairings
rod-shaped bacillus
spore-forming bacillus
Bacillus anthracis
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The lab identified the _____ responsible for the outbreak.
Etymology
Bacillus is a learned borrowing from Latin bacillus, meaning a little staff or wand. It is the diminutive form of the Latin baculum, meaning a stick or staff.
Frequently asked questions
What is a bacillus?
A bacillus is a rod-shaped bacterium. The word can also mean specifically a member of the genus Bacillus, a group that includes some species able to make people ill.
What is the plural of bacillus?
The plural is bacilli.
Are all bacilli harmful?
No. Only some species of bacillus cause disease; many are harmless or even useful, such as those used in antibiotic production.
What is the meaning of bacillus?
"bacillus" (noun) means a member of the bacterial genus Bacillus, made up of organisms shaped like short rods that form spores, some of which are capable of causing illness.
