com·​men·​sal | \ kə-ˈmen(t)-səl How to pronounce commensal (audio) \

Definition of commensal

: of, relating to, or living in a state of commensalism commensal organisms

Other Words from commensal

commensal noun
commensally \ kə-​ˈmen(t)-​sə-​lē How to pronounce commensal (audio) \ adverb

Did you know?

Commensal types, be they human or beast, often "break bread" together. When they do, they are reflecting the etymology of commensal, which derives from the Latin prefix com-, meaning "with, together," jointly and the Latin adjective mensalis, meaning "of the table." In its earliest English uses, "commensal" referred to people who ate together, but around 1870, biologists started using it for organisms that have no use for a four-piece table setting. Since then, the scientific sense has almost completely displaced the dining one.

Examples of commensal in a Sentence

Recent Examples on the Web Danska’s research suggests that the composition of commensal microbes diverges in male and female mice around puberty, so something seems to happen to the bacteria around that time. Melinda Wenner Moyer, Scientific American, 1 Sep. 2021 Two species, both carnivores to a greater or lesser extent, with different nutritional needs, could have a commensal relationship. James Gorman, New York Times, 7 Jan. 2021 Instead of buying time on the array, Breakthrough Listen is tapping into the data stream while the telescope observes its regular targets—a procedure known as commensal observing. Daniel Clery, Science | AAAS, 10 Sep. 2020 In payment, the plants feed their commensal friends with sugars. Jason Pontin, WIRED, 15 June 2018 This turned out to be because the antibiotics also diminished the numbers of tuft cells in the colon; only they, and not commensal bacteria, are required for norovirus infection. Diana Gitig, Ars Technica, 14 Apr. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'commensal.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of commensal

1877, in the meaning defined above

History and Etymology for commensal

Middle English, from Medieval Latin commensalis, from Latin com- + Late Latin mensalis of the table, from Latin mensa table

Learn More About commensal

Time Traveler for commensal

Time Traveler

The first known use of commensal was in 1877

See more words from the same year

Listen to Our Podcast About commensal

Dictionary Entries Near commensal

commend itself to



See More Nearby Entries 

Statistics for commensal

Cite this Entry

“Commensal.” Dictionary, Merriam-Webster, Accessed 12 Aug. 2022.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

More Definitions for commensal


com·​men·​sal | \ kə-ˈmen(t)-səl How to pronounce commensal (audio) \

Medical Definition of commensal

: of, relating to, or living in a state of commensalism

Other Words from commensal

commensal noun
commensally \ -​sə-​lē How to pronounce commensal (audio) \ adverb

More from Merriam-Webster on commensal

Thesaurus: All synonyms and antonyms for commensal


Test Your Vocabulary

Words Named After People

  • name tags
  • Namesake of the leotard, Jules Léotard had what profession?
True or False

Test your knowledge - and maybe learn something along the way.

Universal Daily Crossword

A daily challenge for crossword fanatics.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!