from The American Heritage® Dictionary of the English Language, 4th Edition

  • adj. Of, relating to, or characterized by a symbiotic relationship in which one species is benefited while the other is unaffected.
  • n. An organism participating in a symbiotic relationship in which one species derives some benefit while the other is unaffected.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • adj. of a form of symbiosis in which one organism derives a benefit while the other is unaffected
  • n. An organism partaking in a commensal relationship.

from the GNU version of the Collaborative International Dictionary of English

  • adj. Having the character of a commensal.
  • n. One who eats at the same table.
  • n. An animal, not truly parasitic, which lives in, with, or on, another, partaking usually of the same food. Both species may be benefited by the association.

from The Century Dictionary and Cyclopedia

  • Eating together at the same table.
  • In zoology and botany, living with as a tenant or coinhabitant, but not as a parasite; inquiline. See II., 2.
  • n. One who eats at the same table with another or others.
  • n. In zoology and botany, one of two animals or plants which live together, but neither at the expense of the other; an animal or a plant as a tenant, but not a true parasite, of another; an inquiline.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. either of two different animal or plant species living in close association but not interdependent
  • adj. living in a state of commensalism


Middle English, sharing a meal, from Medieval Latin commēnsālis : Latin com-, com- + Latin mēnsa, table.
(American Heritage® Dictionary of the English Language, Fourth Edition)
From Medieval Latin commensalis. (Wiktionary)


  • These beneficial bugs are called commensal bacteria. - latest science and technology news stories

  • He who lives at the expense of another, and at his table, is his "commensal".

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  • Over millions of years, it has learned to live benignly on human skin and in human nostrils, in a microscopic intimacy that biologists call “commensal,” from the Latin words for “being at table together.”


  • Furthermore, human commensal species, such as great-tailed grackle Quiscalus mexiccanus and bronzed cowbird Molothrus aeneus, normally increase in number around human settlements and result in the loss of nesting success in other birds.

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  • A hush descends on the commensal gathering of friends and relatives the moment the steaming dishes are laid down.


  • The commensal skin bacteria that I am doing research on can be used as a substitute for bathing.

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  • All three are human commensal staple diet: pizza crusts and very, very tolerant of proximity of people, traffic, cats & dogs.

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  • When I took a human-animal interaction class in college, we were taught that cats are not properly considered domesticated but commensal, like a remora or a cowbird but with much more sophisticated social engineering!

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  • Best of all, it is an enthusiastic and stylish picture of the joys of commensal drinking.

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  • Freshwater ostracods are free-living except for members of one group which are commensal on the gills of crayfish.



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