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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Meningitis can be caused by many different types of viruses or bacteria, which are spread through close contact with a person who has them.
From BBC ● Jul. 13, 2026
However, research suggests the MenB vaccine doesn't necessarily prevent transmission of the infection from person to person, doesn't target all the different B bacteria strains and doesn't provide long-term protection.
From BBC ● Jul. 13, 2026
Together, these characteristics allow the bacteria to concentrate where tumors are located while avoiding normal tissues.
From Science Daily ● Jul. 10, 2026
In contrast, a Western-style diet reduced microbial diversity and allowed bacteria linked to dysbiosis to become more abundant.
From Science Daily ● Jul. 10, 2026
I’m holed up in my bedroom looking at microscopic photos of bacteria on the Internet.
From "The Fourteenth Goldfish" by Jennifer L. Holm
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 from cancer patients were more likely to contain specific viruses.
From Science Daily ● Apr. 22, 2026
Bacteria naturally live in the human body and influence both health and disease.
From Science Daily ● Mar. 21, 2026
Bacteria often produce enzymes, like beta-lactamase, to destroy antibiotics.
From BBC ● Dec. 4, 2024
Bacteria feeding on sugars should grow in smooth arcs.
From "The Gene" by Siddhartha Mukherjee
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
Only two decades ago, it was widely doubted by specialists that the Black Death was caused by the bacterium Yersinia pestis, the agent of the bubonic plague.
From The Wall Street Journal ● Jun. 12, 2026
Researchers say the findings indicate the bacterium may help remove nanoplastics from the body by binding to the particles in the intestine and promoting their excretion.
From Science Daily ● May 18, 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
Agricultural use of insect diseases, caused by a bacterium highly specific for certain lypes of insects, is already being tried in California, and more extended tests of this method are under way.
From "Silent Spring" by Rachel Carson
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.
