Etymologically

probabilitas

Etymology and origin of the Latin word probabilitas

Confidence
Established
Formation
Derivation
First attested
81–43 BC, Cicero
Ultimate origin
Latin probus
Etymology tree
inherited borrowed derived
Latin probabilis
Italian probabilmente
Latin probabilitas

Forms

probābilitās f (genitive probābilitātis); third declension[1]

Etymology

It is from Latin probābilis + -tās,[2][3] a word coined by Cicero.[1] Probābilis “credible” comes from probō (“to approve”),[4] and Bianchi & Lelli trace the group to probus (“good, honest”).[5]

Earliest recorded meaning

Cicero uses it in his philosophical works, almost as a technical term of the Academic school, for the quality of seeming true: he warns against being deceived by a captious probābilitās.[3][2][6]

Semantic evolution

In Cicero it is the likelihood on which the Academic wise man acts when certainty is out of reach.[3] Augustine discusses the probābilitās of the Academics, and also uses it of what is judged good by human standards.[3] The TLL finds no plural in ancient Latin.[3] In British Medieval Latin it also meant something likely to be true, a probability.[7] It passed into Italian probabilità and French probabilité,[1][6] and English probability comes from it, partly through French.[8]

Timeline

  • 81–43 BC – Cicero uses it of the appearance of truth in the Academic doctrine.[3][4]
  • 354–430 AD – Augustine writes of the probābilitās of the Academics.[3][4]
  • mid-15th century – English probability is first recorded.[8]

Meanings

Noun

  1. An appearance of truth, probability, plausibility.[2][9][10]
  2. Credibility.[9][1]
  3. (Late Latin) The quality of being judged good or upright.[3]
  4. (Medieval Latin) Something likely to be true, a probability.[7]

References

  1. ^ a b c d Wiktionary, the free dictionary, https://en.wiktionary.org
  2. ^ a b c Glare, P. G. W., ed. (2012), Oxford Latin Dictionary, 2nd ed., Oxford: Oxford University Press
  3. ^ a b c d e f g h Thesaurus linguae Latinae (1900–), Leipzig: Teubner; Berlin: De Gruyter; open-access ed., Munich: Bayerische Akademie der Wissenschaften
  4. ^ a b c Köbler, Gerhard (2010), Lateinisches Abkunfts- und Wirkungswörterbuch für Altertum und Mittelalter, online ed., koeblergerhard.de
  5. ^ Bianchi, Rossella; Lelli, Olga (2014), VOLI: Vocabolario di latino, Florence: Le Monnier
  6. ^ a b Conte, Gian Biagio; Pianezzola, Emilio; Ranucci, Giuliano (2010), il Latino: Vocabolario della lingua latina, 3rd ed., Florence: Le Monnier
  7. ^ a b Latham, R. E., D. R. Howlett, R. K. Ashdowne, et al. (1975–2013), Dictionary of Medieval Latin from British Sources, London: British Academy / Oxford University Press
  8. ^ a b Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
  9. ^ a b Lewis, Charlton T.; Short, Charles (1879), A Latin Dictionary, Oxford: Clarendon Press
  10. ^ Lewis, Charlton T. (1890), An Elementary Latin Dictionary, New York: American Book Company
Cite this entry

“Probabilitas.” Etymologically, 24 Oct. 2026, etymologically.com/la/probabilitas. Accessed 24 Oct. 2026.

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