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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The fever is not harmful, but it can make babies feel crummy as their body is building up antibodies against viruses and bacteria.
From Los Angeles Times ● Jul. 28, 2026
But plaque can shed bacteria or bacterial products into the bloodstream, says Dr. George Hajishengallis, a professor at the University of Pennsylvania’s dental school specializing in microbiology and immunology.
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
The gut microbiome consists of trillions of bacteria that live in the digestive system and affect many aspects of health, including the way the body experiences pain.
From Science Daily ● Jul. 25, 2026
Soon, other scientists connected specific bacteria to diseases such as plague, typhoid fever, and cholera.
From "Ambushed!" by Gail Jarrow
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 are also "promiscuous," easily exchanging genetic material.
From Salon ● Apr. 24, 2025
Bacteria often produce enzymes, like beta-lactamase, to destroy antibiotics.
From BBC ● Dec. 4, 2024
Bacteria, fungi, and plants use this enzyme to oxidize alcohols.
From Science Daily ● Dec. 4, 2024
Bacteria feeding on sugars should grow in smooth arcs.
From "The Gene" by Siddhartha Mukherjee
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
Infant botulism happens when swallowed spores from the bacterium infect a baby’s large intestine and make a toxin in it.
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
According to the researchers, this suggests the kimchi-derived bacterium can continue attaching to nanoplastics even in environments similar to the human digestive tract.
From Science Daily ● May 18, 2026
Allys begins her discussion with some review of the manipulation of the Bt bacterium to create pest-resistant crops, and the introduction of transgenic animals into the food supply decades ago.
From "The Adoration of Jenna Fox" by Mary E. Pearson
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.
