decay

Pronunciation

• IPA: /diˈkeɪ/; /dɪˈkeɪ/ (UK)^[1]

Etymology

It is inherited from Middle English decayen, borrowed from Old Northern French decair (also Anglo-Norman),^[2][3][4] a by-form of decheoir (“to fall, decline”) (modern French déchoir),^[5][6][7] from Vulgar Latin *dēcadō (“to fall off”),^[2][8][9] a refashioning of Latin dēcidō (“to fall off, fall down”),^[4][10][11] from dē- (“down, off”) and cadō (“to fall”),^[8][7] from Proto-Indo-European *ḱad- (“to fall”).^[2][8] It is a doublet of decadence.^[12][10]

Earliest recorded meaning

To decrease: 1475, in the Rolls of Parliament.^[12][2] The noun, a falling off from a thriving condition, is earlier, from about 1460 in Fortescue in the OED,^[7] and 1442 in Barnhart.^[12]

Semantic evolution

Ayto sees in both decay and decadence the notion of a falling off from health or perfection.^[10] The verb meant to decline or deteriorate before 1500, and to rot or decompose from 1580.^[12] The noun followed: wasting away of material things (1523), decline of health (1609, in Shakespeare's Sonnets), and the decomposition of organic tissue (1594).^[7][2] In 18th- and 19th-century use a decay could mean consumption,^[7] and in Scots it survived for "a decline".^[13] Physics adopted it for the decrease of radioactivity in 1897, in Rutherford,^[7][2] and later for the decreasing amplitude of a vibration (1906).^[7]

Timeline

• c. 1460 – the noun, decline.^[7]
• 1475 – the verb, to decrease.^[12]
• before 1500 – to deteriorate.^[12]
• 1580 – to rot.^[12]
• 1594 – decomposition of organic tissue.^[7]
• 1897 – radioactive decay.^[7][2]

Modern meaning

Verb

1. To rot or decompose through the action of bacteria or fungi.
2. To decline gradually in quality, strength or prosperity.
3. (physics) Of a radioactive nucleus or a particle, to break down into another form.
4. Of a satellite, to lose height in its orbit.

Noun

1. The process or state of decaying; rot or decline.

Word family

• decayer
• decayable
• decayless
• semidecay
• nondecaying
• undecaying
• alpha decay
• beta decay

Related words

• deciduous
• decadence
• cadence
• case
• chance

References

1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
3. ^ Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
4. ^ a b Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
5. ^ Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
6. ^ Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
7. ^ a b c d e f g h i j Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
8. ^ a b c The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
9. ^ Weekley, Ernest (1921), An Etymological Dictionary of Modern English, London: John Murray
10. ^ a b c Ayto, John (2005), Word Origins: The Secret Histories of English Words from A to Z, 2nd ed., London: A & C Black
11. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
12. ^ a b c d e f g Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
13. ^ Wright, Joseph, ed. (1898–1905), The English Dialect Dictionary, 6 vols., Oxford: Henry Frowde; via EDD Online 4.0, University of Innsbruck (CC BY 4.0)