Definitions
American Heritage® Dictionary of the English Language, Fourth Edition
- adj. Happening by accident or chance. See Synonyms at accidental.
- adj. Usage Problem Happening by a fortunate accident or chance.
- adj. Usage Problem Lucky or fortunate.
Century Dictionary and Cyclopedia
- Accidental; casual; happening by chance; coming or occurring without any cause, or without any general cause; random.
Wiktionary
- adj. Happening by chance; coincidental or accidental.
- adj. Happening by a lucky chance; lucky or fortunate.
- adj. law Happening independently of human will.
GNU Webster's 1913
- adj. Happening by chance; coming or occuring unexpectedly, or without any known cause; chance.
- adj. (LAw) Happening independently of human will or means of foresight; resulting from unavoidable physical causes.
WordNet 3.0
- adj. occurring by happy chance
- adj. having no cause or apparent cause
Etymologies
- From Latin fōrtuītus. (Wiktionary)
- Latin fortuītus. (American Heritage® Dictionary of the English Language, Fourth Edition)
Examples
“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.”
“The reliance on coincidence or the fortuitous is often questionable, but the results at the same time are never quite incredible.”
“Krutak has been unemployed since quitting a job in July at a nonprofit, timing she called fortuitous in light of the Occupy movement.”
“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.”
“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!”
“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.”
“More probably the resemblance which may be traced in this respect between the religions of the East and West is no more than what we commonly, though incorrectly, call a fortuitous coincidence, the effect of similar causes acting alike on the similar constitution of the human mind in different countries and under different skies.”
Lists
These user-created lists contain the word ‘fortuitous’.
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1100
abound, technology, branch of knowled..., prognosticate, automaton, matron, an older married ..., realm, special field of ..., kingdom, annals, historical records and 981 more...
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GRE 2014
abate, abdicate, abase, aberrant, abeyance, abhor, abjure, abortive, abound, abrasive, abreast, abridge and 1577 more...
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From reading
Collected from reading
venerate, reprobate, reticent, adoration, ethereal, ephemeral, equivocal, contumacious, heinous, solicitous, agnostic, aberration and 335 more...
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common UA vocab. in US
Interesting, there is a traditional vocabulary of an Ukrainian, that differs from vocabulary of average American. It would be nice to explore it.
jackdaw, incongruous, cassock, vivid, magpie, humdrum, amongst, wonder, wandering, wheedling, wheedle, osseous and 368 more...
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GRE
predilection, explicit, appeal, supplication, appealing, enchanting, ovation, pertinent, apropos, opportunely, applicable, germane and 381 more...
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GRE Study guide
Going through the Magoosh website, words I pulled from the verbal section. 2012.
magnanimous, correlate, anglicized, simulacrum, tantamount, obsequiousness, subterfuge, vehement, vociferous, benign, concomitant, veracity and 83 more...
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man gre
abase, abeyance, abreast, abscission, abscond, abyss, accede, accretion, acerbic, acidulous, acumen, adulterate and 483 more...
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GRE 1100
drudgery, implore, hapless, nuance, wrest, incipient, inadvertent, tremulous, bristle, euphemism, disdain, pugnacious and 346 more...
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gre2
aberrant, aberration, aboveboard, abrasive, abstemious, acme, admonish, affable, affluent, alacrity, allegory, alleviate and 1834 more...
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jan_21
magoosh listens
infuriating, galvanize, sporadic, imperciptible, shirk, protean, versatile, auspicious, clairvoyance, nary, predilection, inkling and 63 more...
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Words From Don Quixote
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GRE Reference
A list of words unfamiliar to me that I have repeatedly encountered in GRE question sets.
parochial, clique, salacious, aegis, ostracize, conceited, sacrilegious, inane, serendipity, gourmand, polemic, tenuous and 138 more...
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1100 words you need to know
GRE words
voracious, indiscriminate, eminent, steeped, replete, abound, technology, prognosticate, automaton, matron, paradox, realm and 288 more...
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GRE Words
abjure, unswear, state, rescission, indemnification, ab, reny, abnegate, vitiated, vitiate, adumbrated, abash and 378 more...
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Words I Know
List of most of the words I've learned
garner, abase, abate, abdicate, abduct, aberration, abet, abhor, abide, abject, abjure, abnegation and 1046 more...
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Week 1, Day 1
ignominy, marquee, deter, chariot, stern, perfidy, treacherous, insolent, presumptuous, banish, dubious, livid and 133 more...
Tweets
Looking for tweets for fortuitous.

leaden @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.
http://grammar.about.com/od/alightersideofwriting/a/fortunategloss.htm
http://grammarist.com/usage/fortuitous-fortunate/
http://public.wsu.edu/~brians/errors/fortuitous.html
May 3, 2013
TJay How can "serendipitous" not be a synonym for "fortuitous?" May 3, 2013
biligsiz I've made a fortuitous mistake. Jan 22, 2013
sonofgroucho Wasn't it fortuitous that John came up with the idea of Wordie? Oct 27, 2007
abiohphobia Pronunciation:
\fȯr-ˈtü-ə-təs, -ˈtyü-, fər-\
Etymology:
Latin fortuitus; akin to Latin fort-, fors chance
Date:
1653
1: occurring by chance
a: fortunate, lucky
b: coming or happening by a lucky chance Oct 27, 2007