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dementia

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Etymology and origin of the Latin word dementia

Confidence
Established
Formation
Derivation
First attested
c. 250–184 BC, Plautus
Ultimate origin
Proto-Indo-European (*mn-ti-)

Pronunciation

  • Classical: [deːˈmɛn.ti.a][1]
  • Ecclesiastical: [deˈmɛn.t͡si.a][1]

Forms

dēmentia f (genitive dēmentiae); first declension[1]

Etymology

It is formed from dēmēns (“out of one's mind”) with -ia;[2][3][1] the adjective is dē- (“away from”) and mēns (“mind”).[4][5] De Vaan derives ⟨mēns⟩ from Proto-Italic *mn̥ti- and Proto-Indo-European *mn-ti- (“thought, mind”).[6] Cognate with Sanskrit मति (matí, “thought”) and Lithuanian mintìs (“thought”).[6]

Earliest recorded meaning

Plautus has Mercury say “I'll fill them with error and madness” in the Amphitruo;[2] Köbler gives Cicero as its first author.[7]

Semantic evolution

It is derangement of mind, madness or insanity, and more loosely craziness or folly, as Terence's “such manners! such folly!”.[2][4] Cicero says the ancestors called a state of mind without the light of reason āmentia and also dēmentia.[3][4]

Church Latin glosses it “madness, insanity, foolishness”.[8] English dementia was taken from it in 1806 for a low state of mental function.[5]

Timeline

  • c. 250–184 BC – Plautus of error and madness.[2][7]
  • 190–159 BC – Terence of folly.[2][7]
  • 81–43 BC – Cicero on āmentia and dēmentia.[3][7]
  • 1806 – Borrowed into English as dementia.[5]

Meanings

Noun

  1. Madness, insanity.[2][4][1][8]
  2. Craziness, folly.[2][4][8]

Word family

  • dēmentō

Usage notes

Döderlein contrasts āmentia, a passive lack of reason like an idiot's, with dēmentia, in which a person acts against reason while thinking to act rightly, like a madman; hence āmēns metū but dēmēns scelere.[9] Isidore says dēmentia is a passing failing.[3]

References

  1. ^ a b c d e Wiktionary, the free dictionary, https://en.wiktionary.org
  2. ^ a b c d e f g Glare, P. G. W., ed. (2012), Oxford Latin Dictionary, 2nd ed., Oxford: Oxford University Press
  3. ^ a b c d Thesaurus linguae Latinae (1900–), Leipzig: Teubner; Berlin: De Gruyter; open-access ed., Munich: Bayerische Akademie der Wissenschaften
  4. ^ a b c d e Lewis, Charlton T.; Short, Charles (1879), A Latin Dictionary, Oxford: Clarendon Press
  5. ^ a b c Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
  6. ^ a b de Vaan, Michiel (2008), Etymological Dictionary of Latin and the other Italic Languages, Leiden Indo-European Etymological Dictionary Series 7, Leiden; Boston: Brill
  7. ^ a b c d Köbler, Gerhard (2010), Lateinisches Abkunfts- und Wirkungswörterbuch für Altertum und Mittelalter, online ed., koeblergerhard.de
  8. ^ a b c Stelten, Leo F. (1995), Dictionary of Ecclesiastical Latin, Peabody, Mass.: Hendrickson
  9. ^ Döderlein, Ludwig (1874), Döderlein’s Hand-book of Latin Synonymes, tr. H. H. Arnold, Andover: W. F. Draper
Cite this entry

“Dementia.” Etymologically, 19 Oct. 2026, etymologically.com/la/dementia. Accessed 19 Oct. 2026.

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