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

Gut microbiome balance While around 90% of calories from food are absorbed in the small intestine, some of the remainder (namely, those endemic to the hard-to-digest stuff that survives unscathed, like fiber) are further absorbed by gut bacteria in the colon. —Caroline Tien, SELF, 11 Mar. 2026

For one, the human gut microbiome is complex in its own way. —Jackie Flynn Mogensen, Scientific American, 11 Mar. 2026

Your Mood May Improve Dark chocolate may improve mood, possibly due to a better gut microbiome. —Ann Pietrangelo, Verywell Health, 10 Mar. 2026

Your gut microbiome, which is home to trillions of microbes, plays a key role in everything from digestion to mood. —Stephanie Anderson Witmer, Health, 10 Mar. 2026

Word History

Etymology

micro- + biome

First Known Use

1952, in the meaning defined at sense 1

Rhymes for microbiome

• aplomb
• balaam
• cocom
• embalm
• islam
• pogrom
• salaam
• sitcom
• balm
• bom
• bomb
• calm

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