1
: a community of microorganisms (such as bacteria, fungi, and viruses) that inhabit a particular environment and especially the collection of microorganisms living in or on the human body
Your body is home to about 100 trillion bacteria and other microbes, collectively known as your microbiome.Carl Zimmer
… what's arguably become the hottest area of medicine: microbiome research, an emerging field that's investigating how the bacteria that live in and on our bodies affect our health.Sunny Sea Gold
2
: the collective genomes of microorganisms inhabiting a particular environment and especially the human body
They form one community among the many that make up the human microbiome: the full genetic complement of bacteria and other organisms at home on your skin, gums, and teeth, in your genital tract, and especially in your gut.Nathan Wolfe

Examples of microbiome in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Natto contains probiotics and prebiotics which can help support the gut microbiome and digestion. Michiko Tomioka, CNBC, 5 Sep. 2026 Beneath the cringe internet overshare was a welcome indication that the vaginal microbiome has finally moved from an obscure area of medical research into mainstream conversation. Amy Francombe, Vogue, 4 Sep. 2026 The nutrient plays a critical role in digestive health, blood sugar and cholesterol regulation, and maintaining a healthy gut microbiome. Taylor Nicioli, CNN Money, 4 Sep. 2026 Probiotics are live cultures (bacteria) that can support the overall health of your gut microbiome, or the collection of microorganisms that live in your gastrointestinal tract. Sherri Gordon, HEALTH, 1 Sep. 2026 See All Example Sentences for microbiome

Word History

Etymology

micro- + biome

First Known Use

1952, in the meaning defined at sense 1

Time Traveler
The first known use of microbiome was in 1952

Browse Nearby Words

Cite this Entry

“Microbiome.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/microbiome. Accessed 10 Sep. 2026.

Medical Definition

microbiome

noun
1
: a community of microorganisms (such as bacteria, fungi, and viruses) that inhabit a particular environment and especially the collection of microorganisms living in or on the human body
The intestinal microbiome consists of the microorganisms that inhabit the gut.Clara Abraham et al., The New England Journal of Medicine
Collectively known as the microbiome, this community may play a role in regulating one's risk of obesity, asthma and allergies.Carrie Arnold, Scientific American
The human oral microbiome comprises all microbial species in the oral cavity.Naomi P. O'Grady, The Journal of the American Medical Association
2
: the collective genomes of microorganisms inhabiting a particular environment and especially the human body
As part of a new citizen-science initiative called the American Gut project, the lab sequenced my microbiome—that is, the genes not of "me," exactly, but of the several hundred microbial species with whom I share this body.Michael Pollan, The New York Times
Together, the genomes of these microbial symbionts (collectively defined as the microbiome) provide traits that humans did not need to evolve on their own.Peter J. Turnbaugh et al., Nature
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