bacterium

[bak-teer-ee-uhm]

noun

1. singular of bacteria.

bacterium

/ bækˈtɪərɪəm /

noun

1. the singular of bacteria

bacterium

plural

bacteria 

1. Any of a large group of one-celled organisms that lack a cell nucleus, reproduce by fission or by forming spores, and in some cases cause disease. They are the most abundant lifeforms on Earth, and are found in all living things and in all of the Earth's environments. Bacteria usually live off other organisms. Bacteria make up most of the kingdom of prokaryotes (Monera or Prokaryota), with one group (the archaea) sometimes classified as a separate kingdom.

2. See also archaeon prokaryote

Usage

It is important to remember that bacteria is the plural of bacterium, and that saying a bacteria is incorrect. It is correct to say The soil sample contains millions of bacteria, and Tetanus is caused by a bacterium.

Word History and Origins

Origin of bacterium¹

1840–50; < New Latin < Greek baktḗrion, diminutive of baktēría staff; akin to báktron stick, Latin baculum, bacillum

Example Sentences

These species have an extra outer layer they use to control what gets in and out of a bacterium.

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He injected DNA from one type of bacterium into another, then watched as the two became the same.

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That belief began to shift in 2016, when a bacterium discovered in a Japanese recycling plant was found to survive by consuming plastic waste.

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A new study in Nature highlights the potential of this compound, called CMX410, which targets a key enzyme in Mycobacterium tuberculosis, the bacterium that causes tuberculosis.

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Bubonic plague is the most common type of plague, caused by the bacterium Yersinia pestis, characterised by swollen lymph nodes called "buboes".

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Related Words

• antibody 
• bug 
• disease 
• microbe 
• microorganism 
• pathogen 
• virus