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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Researchers also say there is a lot unknown about cyclospora, which behaves differently and is more difficult to track than other foodborne bacteria like E. Coli or salmonella.
From MarketWatch ● Jul. 30, 2026
When rain falls on parking lots, water runs off carrying metal dust and chemicals from vehicle tires and brake pads, oil and grease from engines and bacteria from trash.
From Los Angeles Times ● Jul. 29, 2026
In particular, they’re examining how bacteria from diseased gums, and the immune response they trigger, may contribute to conditions including heart disease, diabetes, cognitive decline, arthritis, respiratory disease and chronic liver disease.
From The Wall Street Journal ● Jul. 26, 2026
It is a relatively new therapy – not officially recognised by the NHS across the UK – which uses charged gas particles to help kill bacteria on the skin.
From BBC ● Jul. 25, 2026
I should feel lucky it’s not something really bad, like cancer or some rare flesh-eating bacteria.
From "How to Disappear Completely" by Ali Standish
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 naturally live in the human body and influence both health and disease.
From Science Daily ● Mar. 21, 2026
Bacteria evolve quickly, and that adaptability is fueling a growing public health crisis.
From Science Daily ● Feb. 28, 2026
Bacteria are also "promiscuous," easily exchanging genetic material.
From Salon ● Apr. 24, 2025
Bacteria from further underground where it is warmer breed upward to replace the dead ones.
From "The Martian" by Andy Weir
Some governments also use Wolbachia, a naturally occurring bacterium found in about half of all insect species, to curb the spread of mosquito-borne diseases like dengue.
From BBC ● Jul. 23, 2026
The New York company said in a statement that so far its product had not tested positive for the bacterium Clostridium botulinum.
From Los Angeles Times ● Jun. 14, 2026
We are also learning more about the evolutionary history of this devastating bacterium, which has haunted human societies since the Stone Age.
From The Wall Street Journal ● Jun. 12, 2026
The most widespread pathogen was the bacterium Salmonella enterica, which appeared in 63% of the snakes.
From Science Daily ● May 26, 2026
Most important, very little protein entered the bacterium.
From "Double Helix" by James D. Watson
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.
