microbiome
noun
mi·cro·bi·ome
ˌmī-krō-ˈbī-ˌōm 
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
Key Takeaways Fermented foods support gut health by balancing your GI tract microbiome.
—Abby Norman, Verywell Health, 15 Jan. 2026
Soluble fiber supports a healthy gut microbiome, or the balance of gut bacteria.
—Chelsea Rae Bourgeois, Health, 15 Jan. 2026
The second week, the gut and brain will begin to rebalance as hormones like serotonin and dopamine stabilize, gut inflammation drops and the microbiome begins to heal.
—Angelica Stabile, FOXNews.com, 10 Jan. 2026
This lightweight, nourishing oil helps support the skin’s microbiome while delivering deep hydration.
—Colleen Sullivan, InStyle, 10 Jan. 2026
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Cite this Entry
“Microbiome.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/microbiome. Accessed 19 Jan. 2026.
Medical Definition
microbiome
noun
mi·cro·bi·ome
ˌmī-krō-ˈbī-ˌōm
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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