bacterium

[ bak-teer-ee-uhm ]

noun

1. singular of bacteria.

bacterium

/ bækˈtɪərɪəm /

noun

1. the singular of bacteria

bacterium

/ băk-tîr′ē-əm /

, 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

Word History and Origins

Origin of bacterium¹

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

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.

Example Sentences

The advancement was proven to reduce the harmful effects of Staphylococcus epidermidis, a common bacterium known for causing hospital-acquired infections and contributing to antibiotic resistance.

From Science Daily

But listeria, a common and stubbornly persistent type of bacterium, presents unique hurdles.

From Los Angeles Times

It was suggested at the time that the feed was infected with Bacillus cereus bacterium.

From BBC

Klebsiella pneumoniae is a common bacterium that lives in the intestines and is usually harmless.

From BBC

A bacterium, Klebsiella pneumoniae, fends off viruses using a novel mechanism—it creates new genes, a research team has found.

From Science Magazine

Related Words

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