from The American Heritage® Dictionary of the English Language, 5th Edition.

  • adjective Arising from an external cause or factor; not inherent.
  • adjective Biology Of or belonging to a structure that develops in an unusual place.

from The Century Dictionary.

  • In phytogeography, naturalized from a distant formation: opposed to *vicine. A term proposed by Pound and Clements. Compare adventitious, 2.
  • Added extrinsically; not springing from the essence of the subject, but from another source; foreign; accidentally or casually acquired: applied to that which does not properly belong to a subject, but which is superadded or adopted, as in a picture or other work of art, to give it additional power or effect.
  • In botany and zoology, appearing casually, or in an abnormal or unusual position or place; occurring as a straggler or away from its natural position or habitation; adventive.
  • In anatomy, of the nature of adventitia: as, the adventitious coat of an artery.

from the GNU version of the Collaborative International Dictionary of English.

  • adjective Added extrinsically; not essentially inherent; accidental or causal; additional; supervenient; foreign.
  • adjective (Nat. Hist.) Out of the proper or usual place.
  • adjective (Bot.) Accidentally or sparingly spontaneous in a country or district; not fully naturalized; adventive; -- applied to foreign plants.
  • adjective (Med.) Acquired, as diseases; accidental.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • adjective From an external source; not innate or inherent, foreign.
  • adjective Accidental, additional, appearing casually.
  • adjective genetics, medicine Not congenital; acquired.
  • adjective biology Developing in an unusual place or from an unusual source.

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

  • adjective associated by chance and not an integral part


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

[From Latin adventīcius, foreign, from adventus, arrival; see advent.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Latin adventicius ("foreign"), from adveniō ("arrive").


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  • Cuttings are plant pieces, usually stems or branches, capable of growing new roots, called adventitious roots.

    5. How plants live and grow 1991

  • Leaf-buds occasionally arise from the roots, when they are called adventitious; this occurs in many fruit trees, poplars, elms and others.

    Encyclopaedia Britannica, 11th Edition, Volume 2, Part 1, Slice 1 Various

  • But as it was occasionally inexpedient to carry about measuring-chains a boy would do well to know the precise length of his own foot-pace, so that when he was deprived of what Hurree Chunder called adventitious aids 'he might still tread his distances.

    Kim Rudyard Kipling 1900

  • But as it was occasionally inexpedient to carry about measuring-chains a boy would do well to know the precise length of his own foot-pace, so that when he was deprived of what Hurree Chunder called adventitious aids’ he might still tread his distances.

    Kim 2003

  • In one of David Attenborough's 'The Private Life Of Plants' episodes, he talks on similar fallen trunks that eventually give rise to a row of other daughter 'trees' growing out of the main trunk; these eventually grow adventitious roots and become independent.

    An undead tree AYDIN 2009

  • If Barnes once called the contest "posh bingo", this year looks a lot less adventitious.

    The Man Booker judges seem to find reading a bit hard | Catherine Bennett 2011

  • Third, probably very few of the participants (other than perhaps adventitious semi-professional looters) expected to gain anything in terms of significant personal profit or meaningful social betterment as a consequence of the upheavals in Los Angeles.

    Matthew Yglesias » Endgame 2010

  • Things he did, no matter how adventitious or spontaneous, struck the popular imagination as remarkable.

    Chapter XI 2010

  • As Meeker sees comedy as having a biological rather than idealistic focus, so Baillie sees it as properly centering on the “original distinctions of nature” rather than on the “adventitious distinctions ... of age, fortune, rank, profession, and country” (13).

    Joanna Baillie’s Ecotopian Comedies 2008

  • The skilled reader is not dependent on the adventitious aids of easiness or brightness; he is no longer, for instance, dependent upon plot for his enjoyment of fiction, or upon what is called 'actuality' or 'incident', or mere verisimilitude of description.

    2010 January 08 | NIGEL BEALE NOTA BENE BOOKS 2010


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  • See calcareous for a usage note.

    February 23, 2008

  • For some reason, this always sounds madeupical to me. :-)

    February 24, 2008

  • Totally madeupical.

    February 25, 2008

  • JM is relaxed about adventitious adventures.

    June 13, 2010

  • From p. 104 of F. Scott Fitzgerald's The Great Gatsby: "Someone with a positive manner, perhaps a detective, used the expression 'madman' as he bent over Wilson's body that afternoon, and the adventitious authority of his voice set the key for the newspaper reports next morning."

    September 29, 2012

  • "It had something to do with love. About the essential brutality of love. About those adventitious souls who deliberately seek out love as a prime agent of total self-immolation."

    Pond by Claire-Louise Bennett, p 11

    April 19, 2017