Etymologically

rationalis

Etymology and origin of the Latin word rationalis

Confidence
Established
Formation
Derivation
First attested
Celsus
Ultimate origin
Latin (ratiō)

Pronunciation

  • IPA (Classical): [ra.ti.oːˈnaː.lɪs][1]
  • IPA (Ecclesiastical): [rat.t͡si.oˈnaː.lis][1]

Forms

ratiōnālis (neuter ratiōnāle, adverb ratiōnāliter); third-declension two-termination adjective[1]

Etymology

It is from ratiō “reckoning, reason” with the suffix -ālis.[2][1][3]

Earliest recorded meaning

The OLD's earliest citation is from Celsus, of the theoretical school of medicine.[2] Köbler dates Celsus 14–37 AD and also cites Seneca.[4]

Semantic evolution

It meant concerned with reasoning, theoretical, and as a plural noun the theoreticians, in Celsus; possessing reason, rational, as in Seneca and Quintilian; and of accounts, with ratiōnālis as a noun for an accountant, a treasury official of the Empire.[2][5][6]

In Medieval Latin it meant reasonable, in accordance with reason; of fields, measured by survey; and as a noun a burgomaster.[7] The neuter ratiōnāle was the breastplate of the Hebrew high priest and a bishop's liturgical ornament.[7] British Medieval Latin used it for endowed with reason, and as a noun a rational creature.[8] English rational (late 14th century) and English rationale (1650s, from Late Latin ratiōnāle) are from it.[3]

Timeline

  • 14–37 AD – Celsus uses it.[2][4]
  • 4 BC–65 AD – Seneca uses it of beings with reason.[2][4]
  • late 14th century – English rational is recorded.[3]

Meanings

Adjective

  1. Theoretical, of reasoning.[2]
  2. Possessing reason, rational.[2]
  3. Of accounts.[2]
  4. (Medieval Latin) Reasonable, (of fields) surveyed.[7]

Noun

  1. An accountant, a treasury official.[2][5]
  2. (Ecclesiastical Latin) (ratiōnāle) The high priest's breastplate; a bishop's ornament.[7]

Word family

  • irratiōnālis
  • ratiōnālitās

References

  1. ^ a b c d Wiktionary, the free dictionary, https://en.wiktionary.org
  2. ^ a b c d e f g h i Glare, P. G. W., ed. (2012), Oxford Latin Dictionary, 2nd ed., Oxford: Oxford University Press
  3. ^ a b c Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
  4. ^ a b c Köbler, Gerhard (2010), Lateinisches Abkunfts- und Wirkungswörterbuch für Altertum und Mittelalter, online ed., koeblergerhard.de
  5. ^ a b Gaffiot, Félix (2016), Dictionnaire latin-français, new ed. by Gérard Gréco et al. (Gaffiot 2016), online ed.
  6. ^ Lewis, Charlton T.; Short, Charles (1879), A Latin Dictionary, Oxford: Clarendon Press
  7. ^ a b c d Niermeyer, J. F. (1976), Mediae Latinitatis Lexicon Minus, Leiden: Brill
  8. ^ 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
Cite this entry

“Rationalis.” Etymologically, 16 Oct. 2026, etymologically.com/la/rationalis. Accessed 16 Oct. 2026.

Last edited on . ·