dementia

Etymology

It is borrowed from Latin dēmentia (“madness, insanity, folly”),^[2][3][4][5] from the stem of dēmēns (“mad, out of one's mind”), the source of dement, with the abstract noun suffix -ia.^[2][4][6] The Latin adjective is formed from the phrase dē mente (“out of the mind”).^[4] English had earlier used demency, from démence, from the 1520s.^[4][2]

Earliest recorded meaning

Insanity, especially affecting thought and judgement: 1598, in J. Mosan's translation of C. Wirsung's Praxis Medicinae, according to the revised OED.^[2] Etymonline and Merriam-Webster date the word to 1806,^[4][7] the Oxford Dictionary of English and the Shorter Oxford to the late 18th century,^[8][9] and Dictionary.com to 1800–10.^[6]

Semantic evolution

The word passed from general madness to a medical term for a progressive decline of memory and reasoning caused by disease of the brain.^[2][9][7] Senile dementia, the failure of mind in old age, is recorded from 1822.^[4] Dementia praecox, a Modern Latin name for what is now called schizophrenia, was used in English from 1899, after German (1891) and démence précoce (1857).^[4][9] A general sense, loss of judgement or wild foolishness, is recorded from 1846.^[2][9]

Timeline

• 1520s – demency, from French.^[4]
• 1598 – insanity.^[2]
• 1806 – a low condition of mental function.^[4][7]
• 1822 – senile dementia.^[4]
• 1846 – foolishness, loss of judgement.^[2]
• 1899 – dementia praecox.^[4]

Modern meaning

Noun

1. (medicine) A usually progressive condition, such as Alzheimer's disease, in which the brain's memory, reasoning and other cognitive abilities decline.
2. Madness or folly; a complete loss of judgement.

Word family

• demential
• dementia praecox
• senile dementia

Related words

• amentia
• demented
• dement
• mental
• mind

References

1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
4. ^ a b c d e f g h i j k Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
5. ^ Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
6. ^ a b Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
7. ^ a b c Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
8. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
9. ^ a b c d Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press