Dictionary

black swan en · NOUN

Pronunciation

• /blæk ˈswɑn/ (General-American)
• /blæk ˈswɒn/ (Received-Pronunciation)
• (General-American) audio

Etymology

From Middle English blak swan, calqued from a Latin quotation from Satire VI (written late 1st century – early 2nd century B.C.E.) of the Roman poet Juvenal: “Rara avis in terris, nigroque simillima cygno [a bird as rare upon the earth as a black swan]!”. Equivalent to black + swan. Sense 2.1 (“something believed impossible or not to exist”) is from the fact that all swans were thought to have white plumage until black swans were discovered in Australia in the 17th century by Dutch explorers. Sense 2.2 (“rare and hard-to-predict event”) was popularized by the Lebanese-American author Nassim Nicholas Taleb (born 1960) in his book The Black Swan: The Impact of the Highly Improbable (2007): see the quotation.

Meanings

1. Cygnus atratus, a swan with black plumage and a red bill which is endemic to Australia.
   • The original propounder of 'all swans are white' presumably based it on a sample of hundreds or thousands; but the verifications before the Australian black swan was discovered must have run into millions 1961, Harold Jeffreys, “Estimation Problems”, in Theory of Probability (Oxford Classic Texts in the Physical Sciences), 3rd edition, Oxford, Oxfordshire: Clarendon Press, published 2003, →ISBN, paragraph 3.21, page 132:
   • If you tell me that there is or that there is not a black swan or a white raven, I want to know where you mean; and that you can only show me,—no description will answer the purpose. 1884 summer, Charles Sanders Peirce, “On the Algebra of Logic (Second Paper) [Item 22, MS 508]”, in Christian J. W. Kloesel [et al.], editors, Writings of Charles S. Peirce: A Chronological Edition, volumes 5 (1884–1886), Bloomington; Indianapolis, Ind.: Indiana University Press, published 1993, →ISBN, page 111:
   • Mankind were wrong, it seems, in concluding that all swans were white: are we also wrong, when we conclude that all men's heads grow above their shoulders, and never below, in spite of the conflicting testimony of the naturalist Pliny? As there were black swans, though civilised people had existed for three thousand years on the earth without meeting with them, may there not also be "men whose heads do grow beneath their shoulders," notwithstanding a rather less perfect unanimity of negative testimony from all observers? Most persons would answer No; it was more credible that a bird should vary in its colour, than that man should vary in the relative position of his principal organs. 1843, John Stuart Mill, “Of the Ground of Induction”, in A System of Logic, Ratiocinative and Inductive, being a Connected View of the Principles of Evidence, and the Methods of Scientific Investigation. […], volume I, London: John W[illiam] Parker, […], →OCLC, § 3, page 379:
   • This concept of "observation" is not like that of seeing a black swan, to mention a famous classical example. New particles leave signatures in the detector that on an event by event basis cannot be distinguished by other processes (background). 1999, G. D’Agostini, “Bayesian Reasoning versus Conventional Statistics in High Energy Physics”, in Wolfgang von der Linden, Volker Dose, Rainer Fischer, Roland Preuss, editors, Maximum Entropy and Bayesian Methods: Garching, Germany 1998: Proceedings of the 18th International Workshop on Maximum Entropy and Bayesian Methods of Statistical Analysis (Fundamental Theories of Physic; 105), Dordrecht, South Holland: Springer Science+Business Media, →DOI, →ISBN, footnote 19, page 166:
2. (figuratively) Something believed impossible or not to exist, especially if an example is subsequently found; also, something extremely rare; a rara avis.
   • A Virgin too, untouch'd, and chaſte, / VVhom Man ne'er took about the VVaiſte. / She's a rare Bird! find her vvho can, / And much reſembling a black Svvan. 1743, Henry Fielding, “Part of Juvenal’s Sixth Satire, Modernized in Burlesque Verse”, in Miscellanies, […], volume I, London: […] A[ndrew] Millar, […], →OCLC, page 97:
   • I do but ſpeake in the perſon of Demetrius, & vnder Hippolita ſhadovv vvhat I intend to the rare, and neuer enough vvondred at Moſpa, the black ſvvan of beauty, & madg-hovvled of admiration. 1605 (date written), Iohn Day [i.e., John Day], The Ile of Guls. […], London: […] [John Trundle], and are to bee sold by Iohn Hodgets […], published 1606, →OCLC, signature [D4], verso:
3. (also, attributive, figuratively, specifically) A rare and hard-to-predict event with major consequences.
   • Worried that Greece could go belly up? So-called black swan funds – named for rare and unexpected events – offer a way to profit in the event of a market collapse. 2011 June 29, Azam Ahmed, “New investment strategy: Preparing for end times”, in The New York Times, New York, N.Y.: The New York Times Company, →ISSN, →OCLC, archived from the original on 23 Dec 2022:
   • A small number of Black Swans explain almost everything in our world, from the success of ideas and religions, to the dynamics of historical events, to elements of our own personal lives. […] Fads, epidemics, fashion, ideas, the emergence of art genres and schools. All follow these Black Swan dynamics. 2007, Nassim Nicholas Taleb, “Prologue”, in The Black Swan: The Impact of the Highly Improbable, New York, N.Y.: Random House, →ISBN, page xviii:
   • The details of this catastrophe [the 2011 Fukushima nuclear accident] were unforeseeable, leading some to conclude this was a black swan event – something so wildly unexpected, so enormous in its impact, that it seems to defy our understanding and expose the fragility of our knowledge of the world. How could anyone have predicted this? […] In the face of black swans – also known as fat-tail events, for the way their occurrences are distributed along a probability curve – market pricing may be impossible. 2011 March 19, Jeff Sommer, “A crisis that markets can’t grasp”, in The New York Times, New York, N.Y.: The New York Times Company, →ISSN, →OCLC, archived from the original on 03 Feb 2023:

Forms

Deriveds

black swan event · black swan theory · black swan fallacy

Hypernyms

Cygnus (Cygnus atratus) · Anatidae (Cygnus atratus) · Anserinae (Cygnus atratus)

Relateds

tail risk

Synonyms

unicorn · rara avis · hen's tooth · lightning in a bottle · rocking horse shit · unicorn · rarity · black swan · one in a million · rare bird · rarity · rare bird

Translations (88)

he ברבור שחור (Cygnus atratus) · de Trauerschwan (Cygnus atratus) · eu beltxarga beltz (Cygnus atratus) · ro leprechaun (something believed impossible or not to exist, especially if an example is subsequently found) · my ငန်းနက် (Cygnus atratus) · sk labuť čierna (Cygnus atratus) · el μαύρος κύκνος (Cygnus atratus) · sc sìsini nieddu (Cygnus atratus) · sh цр̑нӣ ла̏бӯд (Cygnus atratus) · cmn 黑天鵝 /黑天鹅 (Cygnus atratus) · pl czarny łabędź (something believed impossible or not to exist, especially if an example is subsequently found) · ta கறுப்பு அன்னம் (Cygnus atratus) · cy alarch du (Cygnus atratus) · sv svart svan (Cygnus atratus) · nv dééshzhiin (Cygnus atratus) · gl cisne negro (Cygnus atratus) · fi musta joutsen (something believed impossible or not to exist, especially if an example is subsequently found) · it mosca bianca (something believed impossible or not to exist, especially if an example is subsequently found) · cs labuť černá (Cygnus atratus) · da sortsvane (Cygnus atratus) · gd eala dhubh (Cygnus atratus) · sl črni labod (Cygnus atratus) · lv melnais gulbis (Cygnus atratus) · tr kara kuğu (Cygnus atratus) · cmn 黑天鵝 /黑天鹅 (something believed impossible or not to exist, especially if an example is subsequently found) · fo svartisvanur (Cygnus atratus) · kum къара къув (Cygnus atratus) · cmn 黑天鵝 /黑天鹅 (rare and hard-to-predict event with major consequences) · ro lebădă neagră (Cygnus atratus) · se čáhppesnjukča (Cygnus atratus) · ca cigne negre (Cygnus atratus) · pl czarny łabędź (rare and hard-to-predict event with major consequences) · fi mustajoutsen (Cygnus atratus) · bn কালো রাজহাঁস (Cygnus atratus) · eo nigra cigno (Cygnus atratus) · ko 흑고니 (Cygnus atratus) · ru чёрный ле́бедь (Cygnus atratus) · mrj шим йӱксӹ (Cygnus atratus) · nl zwarte zwaan (Cygnus atratus) · es mirlo blanco (something believed impossible or not to exist, especially if an example is subsequently found) · id angsa hitam (Cygnus atratus) · uk лебідь чорний (Cygnus atratus) · br alarc'h du (Cygnus atratus) · nys maali (Cygnus atratus) · hi काला हंस (Cygnus atratus) · udm сьӧд юсь (Cygnus atratus) · sq mjellma e zezë (Cygnus atratus) · wth kunawarr (Cygnus atratus) · pcd chin·nhe nòre (Cygnus atratus) · pnb کالا ہنس (Cygnus atratus) · es cisne negro (Cygnus atratus) · ml കറുത്ത അരയന്നം (Cygnus atratus) · is svartsvanur (Cygnus atratus) · ar تَمّ أَسْوَد (Cygnus atratus) · ga eala dhubh (Cygnus atratus) · fr cygne noir (Cygnus atratus) · et mustluik (Cygnus atratus) · kbd къыуфӏыцӏэ (Cygnus atratus) · kn ಕಪ್ಪು ಹಂಸ (Cygnus atratus) · uk чорний лебідь (Cygnus atratus) · fi musta joutsen (rare and hard-to-predict event with major consequences) · la rāra avis (something believed impossible or not to exist, especially if an example is subsequently found) · pl łabędź czarny (Cygnus atratus) · hu fekete hattyú (Cygnus atratus) · oc cicne negre (Cygnus atratus) · mk црн лебед (Cygnus atratus) · sh cȓnī lȁbūd (Cygnus atratus) · lt juodoji gulbė (Cygnus atratus) · fa قوی سیاه (Cygnus atratus) · nn svartsvane (Cygnus atratus) · vi thiên nga đen (Cygnus atratus) · it cigno nero (Cygnus atratus) · th หงส์ดำ (Cygnus atratus) · pt cisne-negro (Cygnus atratus) · fy swarte swan (Cygnus atratus) · nb sort svane (something believed impossible or not to exist, especially if an example is subsequently found) · ja 黒鳥 (Cygnus atratus) · hy սև կարապ (Cygnus atratus) · be чорны лебедзь (Cygnus atratus) · az qara qu quşu (Cygnus atratus) · wyi gannawarra (Cygnus atratus) · nb svartsvane (Cygnus atratus) · ms joyinah hitam (Cygnus atratus) · fr cygne noir (something believed impossible or not to exist, especially if an example is subsequently found) · mk црн лебед (something believed impossible or not to exist, especially if an example is subsequently found) · ota قره قوغو (Cygnus atratus) · bg че́рен ле́бед (Cygnus atratus) · af swartswaan (Cygnus atratus)

wikipedia: Juvenal · wikipedia: Nassim Nicholas Taleb · wikipedia: The Black Swan: The Impact of the Highly Improbable · wikipedia: Random House