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

  • adjective Happening by accident or chance. synonym: accidental.
  • adjective Resulting in good fortune; lucky.

from The Century Dictionary.

  • Accidental; casual; happening by chance; coming or occurring without any cause, or without any general cause; random.

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

  • adjective Happening by chance; coming or occuring unexpectedly, or without any known cause; chance.
  • adjective (LAw) Happening independently of human will or means of foresight; resulting from unavoidable physical causes.

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

  • adjective Happening by chance; coincidental or accidental.
  • adjective Happening by a lucky chance; lucky or fortunate.
  • adjective law Happening independently of human will.

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

  • adjective occurring by happy chance
  • adjective having no cause or apparent cause


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

[Latin fortuītus; see bher- in Indo-European roots.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Latin fōrtuītus.


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  • Hence there grew up the belief that events which we describe as fortuitous or random or subject to chance are no different from any other happenings, except that we do not know why they happen.


  • For very many in the world attribute everything to themselves and their prudence, and what they cannot so attribute they call fortuitous and accidental, not knowing that human prudence is nothing and that "fortuitous" and "accidental" are idle words.

    Angelic Wisdom about Divine Providence Emanuel Swedenborg 1730

  • The reliance on coincidence or the fortuitous is often questionable, but the results at the same time are never quite incredible.

    Great Scot 2004

  • The reliance on coincidence or the fortuitous is often questionable, but the results at the same time are never quite incredible.

    Great Scot 2004

  • Krutak has been unemployed since quitting a job in July at a nonprofit, timing she called fortuitous in light of the Occupy movement.

    Yahoo! News: Business - Opinion 2011

  • A careful induction from all the passages where this number cannot be regarded as fortuitous, but is evidently of Divine ordinance and appointment (I call fortuitous such sevens as occur, Acts xix. 14; xx. 6), will leave no doubt that it claims throughont Scripture to be considered as the covenant number, the sign and signature of God's covenant relation to mankind, and above all to that portion of mankind with which this relation is not potential merely, but actual, namely the Church.

    Epistles to the Seven Churches in Asia. 1807-1886 1863

  • And he concludes, after referring to the fortuitous duty-free shopping interlude I shared with Bashar en route back to London from Damascus, by remarking: By this time, Michael, whos a very engaging personality, is a friend of the family!

    A Question of Honour Lord Michael Levy 2008

  • Yet all of the various elements which have historically been assigned to Fortune, Fate, and Chance are gathered into a single providential system of which the fortuitous is a part.


  • Since Fortuna is a personification of the fortuitous, and the fortuitous is a branch of the chain of causality, its normal place in the providential scheme is within the realm of Fate, which is the unfolding of Providence in multiplicity and time.


  • An event that is described as fortuitous or accidental in the context of one set of interests may take on a different aspect when it is surveyed from another standpoint, being seen there as intrinsically related to the historian's principal theme or subject: in neither case, though, need the suggestion that it has no causal explanation be present.



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  • Pronunciation:

    \fȯr-ˈtü-ə-təs, -ˈtyü-, fər-\


    Latin fortuitus; akin to Latin fort-, fors chance



    1: occurring by chance

    a: fortunate, lucky

    b: coming or happening by a lucky chance

    October 27, 2007

  • Wasn't it fortuitous that John came up with the idea of Wordie?

    October 27, 2007

  • I've made a fortuitous mistake.

    January 22, 2013

  • How can "serendipitous" not be a synonym for "fortuitous?"

    May 3, 2013

  • @TJay:

    Although some, seeking pomposity, substitute fortuitous for fortunate, the words are not synonymous. Fortunate means “lucky.” Fortuitous means “by chance,” “by accident.” Something that is fortuitous can also be fortunate, but unless it happened by chance, fortunate is the correct word.

    – Rene J. Cappon, The Associated Press Guide to Writing, Peterson’s, 2000

    That’s the usage problem to which the AHD entries refer. Until recently, “fortuitous” meant “accidental”, not “lucky”. (See the CDC definition.) In the twentieth century some English speakers began to conflate fortuitous with fortunate and using it to mean (as you say) serendipitous. Some audiences regard this usage as confused or pompous, and a good dictionary won’t include it without a warning.

    May 4, 2013

  • occurring by happy chance; having no cause or apparent cause

    Though Maria's neighbor Ernie "bumped into" her at the Farmer's Market, the encounter wasn't nearly as fortuitous as Maria was led to believe: Ernie desperately wanted to ask Maria out on a date and had been following her about town.

    October 12, 2016