curdle

Etymology

It is formed from English curd + -le, with the frequentative suffix, on the verb meaning to make into curd,^[2][3][4][5] a verb now obsolete.^[6][7] That verb is from Middle English crudden (“to coagulate, congeal”), also curden, from the noun crud (“curd”).^[8][9] The older form of the English frequentative was crudle, which Etymonline dates to the 1580s and Barnhart to 1590, in Spenser's “Faerie Queene”,^[3][9] and the Shorter Oxford notes that cruddle survives in dialect.^[4] The noun's sounds r and u changed places in the 15th century, according to Ayto.^[10] Further back, Hoad calls the noun of unknown origin and compares Scottish Gaelic gruth (“curds”),^[5] Ayto also says the ultimate ancestry is not known,^[10] and Barnhart, Klein and Merriam-Webster connect it with Old English crūdan (“to press, drive”), the source of crowd.^[9][11][12]

Earliest recorded meaning

To make blood thicken or clot, in the phrase to curdle the blood: 1579, in Spenser's Shepheardes Calender.^[2] The literal sense of forming milk into curd is recorded from 1585, in Banister's Compendious Chyrurgerie.^[2]

Semantic evolution

The figurative blood came first in the OED's record, and it has stayed with the word: from 1613 blood itself is said to curdle, chiefly of fear or dread,^[2] and Etymonline finds that curdling has almost always been used of blood in this figurative way since the 1690s.^[3] The kitchen sense spread from milk to sauces and custards, which separate into soft lumps and liquid,^[2] and the verb became intransitive in 1586, in Newton's Olde Mans Dietarie.^[2] Johnson (1755) defined it as to cause to coagulate, or to force into concretions.^[13] From 1753 something could curdle figuratively, as a good feeling turns sour,^[2] and the figurative transitive use, to condense or to spoil, is recorded from 1816, in Byron.^[2] American underworld slang used it from 1940 of a scheme that goes wrong.^[14]

Timeline

• 1579 – to curdle the blood, to thicken it, and figuratively to afflict with fear.^[2]
• 1585 – to form milk into curd.^[2]
• 1586 – intransitive, of milk or cream, to form curd.^[2] Merriam-Webster's Unabridged dates this use to 1590.^[12]
• before 1591 – noun, the act or product of curdling.^[2]
• 1611 – to form a solid thing by curdling, in Job x. 10 in the King James Bible.^[2]
• 1613 – intransitive, of blood, to clot, chiefly figuratively.^[2]
• 1753 – intransitive and figurative, to thicken, or to turn sour.^[2]
• 1816 – transitive and figurative, to spoil or tarnish.^[2]
• 1940 – American underworld slang, of a plan, to misfire.^[14]

Meanings

Verb

1. To separate, or make a liquid separate, into soft lumps and thin liquid; to form curds: The custard curdled when the oven ran too hot.^{[15][7][12][2]}
2. To congeal or coagulate; to become thick and lumpy.^[16][12]
3. To turn sour or go bad, or to make something do so: Their friendship curdled into resentment.^[16][12][2]
4. curdle someone's blood: to fill someone with fear or horror.^[15][7][2]

Noun

1. (rare) The act or product of curdling; a curd.^[4][2]

Word family

• curdler

Related words

• curd
• crud
• crowd
• bloodcurdling

Usage notes

A dialect word curdle, a curl of hair or a ripple in water, is a variant of curl with an added d: the OED records it from 1821, in J. Clare, and the English Dialect Dictionary locates it in Wiltshire, Somerset, Devon and Northamptonshire.^[2][17] In Derbyshire curdle also meant to creep together for warmth or protection.^[17]

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h i j k l m n o p q r s t u Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
4. ^ a b c Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
5. ^ a b Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
6. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
7. ^ a b c Soanes, Catherine; Stevenson, Angus, eds. (2004), Concise Oxford English Dictionary, 11th ed., Oxford: Oxford University Press
8. ^ Kurath, Hans; Kuhn, Sherman M.; Lewis, Robert E., eds. (1952–2001), Middle English Dictionary, Ann Arbor: University of Michigan Press; online edition ed. Frances McSparran et al. (2000–2018)
9. ^ a b c Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
10. ^ a b Ayto, John (2005), Word Origins: The Secret Histories of English Words from A to Z, 2nd ed., London: A & C Black
11. ^ Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
12. ^ a b c d e Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
13. ^ Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
14. ^ a b Green, Jonathon (2010), Green's Dictionary of Slang, London: Chambers; digital ed. 2016–, https://greensdictofslang.com
15. ^ a b Collins English Dictionary (2023), Glasgow: HarperCollins
16. ^ a b The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
17. ^ a b 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)