Plural word for bacteria Bacteria is the plural form of the singular bacterium. Because microscopic bacterium is most often found in multiples, the plural form bacteria is more commonly used. The plurals of several other singular words ending in -um are also formed this way, such as memorandum/memoranda and curriculum/curricula. The irregular noun bacterium’s plural derives directly from its original pluralization in Latin and Greek. Bacteria is sometimes treated as a singular collective noun. However, this is not standard in English, and bacteria should be treated as a plural form.
Some bacteria are beneficial to humans (for example, those that live in the stomach and aid digestion), and some are harmful (for example, those that cause disease).
First recorded in 1860–65; from New Latin, from Greek baktḗria, plural of baktḗrion, diminutive of baktēría “staff, cane”; see origin at bacterium
First recorded in 1860–65; from New Latin; see origin at bacteria ( def. )
Bacteria are microscopic living organisms, usually one-celled, that can be found everywhere. They can be dangerous, such as when they cause infection, or beneficial, as in the process of fermentation (such as in wine) and that of decomposition. In 1676, Anton Van Leeuwenhoek first observed bacteria through a microscope and called them “animalcules.” In 1838, the German Naturalist Christian Gottfried Ehrenberg called them bacteria, from the Greek baktḗria, meaning "little stick." An apt word, as the first observed bacteria were shaped like rods, although bacteria can also be spiral or spherical in shape. A grammar note: The word bacteria is the plural form of "bacterium" and so should be written as plural, as in "Many bacteria are harmless."
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Yogurt is generally tolerated better than other dairy, particularly Greek yogurt or yogurts rich in probiotic bacteria, says Sibley.
From The Wall Street Journal ● Oct. 12, 2026
Beneficial microbes may also help suppress harmful bacteria or make it more difficult for disease-causing organisms to thrive.
From Science Daily ● Oct. 11, 2026
The research work included testing stem cell production, creating and testing IV fluid, and studying how the bacteria that causes pneumonia can lead to long‑term heart damage.
From Los Angeles Times ● Oct. 8, 2026
"You're altering the microbiome of your gut, and perhaps creating antibiotic resistant bacteria in your body that will fight off the drug therapy the next time you really need it," he said.
From Barron's ● Oct. 8, 2026
Once you do drag his mind off bacteria and injuries, he’s okay.
From "Liar, Liar" by Gary Paulsen
Bacteria in treated trees have dropped by at least 90%.
From The Wall Street Journal ● Sep. 19, 2026
Bacteria can also infect wounds where screwworm maggots are present and may cause an infection that can lead to symptoms like fever or chills.
From Los Angeles Times ● Jun. 6, 2026
Bacteria and viruses can hide inside amoebae, where they may be shielded from disinfectants and other treatment methods.
From Science Daily ● Jun. 6, 2026
Bacteria evolve quickly, and that adaptability is fueling a growing public health crisis.
From Science Daily ● Feb. 28, 2026
Bacteria and a host of other microorganisms could find their way into cultures from people’s unwashed hands, their breath, and dust particles floating through the air, and destroy them.
From "The Immortal Life of Henrietta Lacks" by Rebecca Skloot
Plague is a disease caused by the Yersinia pestis bacterium, the same pathogen that killed millions of people in Europe during the Middle Ages.
From Barron's ● Oct. 7, 2026
The bacterium that causes the plague, Yersinia pestis, found among rodents such as marmots in the area.
From BBC ● Oct. 7, 2026
The bacterium Yersinia pestis, which can cause pneumonic and bubonic plagues, has been identified from time to time in Siberia, linked to exposure to vermin.
From The Wall Street Journal ● Oct. 5, 2026
The bacterium still persists in natural rodent reservoirs in several regions.
From Science Daily ● Sep. 20, 2026
Pneumococcal pneumonia after influenza infection—the epidemic within the epidemic—was of such concern that the ministry had deployed teams of scientists to study the bacterium and develop a vaccine against it.
From "The Gene" by Siddhartha Mukherjee
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
