flux

Etymology

It is inherited from Middle English flux, early also flix,^[2][3][4] borrowed from Old French flux (Etymonline gives flus),^[3][5][2][6] or directly from Latin flūxus (“a flowing, flow”),^[2][5][4][7] a noun from the past participle of fluō (“to flow”),^[8][9][6] from Proto-Indo-European *bhleu-.^[8] The OED explains the early form flix by the French pronunciation of the vowel.^[3] In Anglo-Norman the noun is recorded from the second quarter of the 13th century, already for a discharge of body fluid, bleeding and dysentery.^[10] Ayto notes that the Latin verb is similar in form and meaning to flow but unrelated to it.^[9] The verb is formed from the noun.^[3][11][4]

Earliest recorded meaning

An abnormal flow of blood or other fluid from the body, especially from the bowels; also an early name for dysentery: 1377, in Langland's Piers Plowman.^[3][5] Barnhart finds the form flix for an excessive flow of blood about 1350.^[2][12]

Semantic evolution

From the medical sense the word widened to any flowing (about 1600) and to the incoming tide, as in flux and reflux (1612),^[3][4][7] and to a stream of people, already in Shakespeare's As You Like It.^[3] The sense "a continuous succession of changes", which gave in a state of flux, is first recorded in Francis Bacon's Essays (1625).^[3][2][4] In chemistry and metallurgy a flux became a substance mixed with a metal to help it melt, from the early 18th century,^[4][7] and in physics the rate of flow of a fluid, energy or particles across an area.^[4][13] The verb meant to make fluid or melt from 1477, in Thomas Norton's Ordinall of Alchimy;^[3] in medicine it meant to purge a patient, or make one salivate (1666–1785),^[3][4] which gave 18th-century slang senses "to salivate" and "to cheat".^[14][3] The adjective flux, changing or inconstant, was used from about 1677 to 1797.^[3][4]

Timeline

• c. 1350 – flix, an excessive flow of blood.^[2]
• 1377 – an abnormal discharge from the body; dysentery.^[3][5]
• 1477 – verb, to make fluid, melt.^[3]
• c. 1600 – the action of flowing.^[3]
• 1612 – the flowing in of the tide.^[3]
• 1625 – a continuous succession of changes.^[3][2]
• 1666 – verb, to purge or salivate a patient (obsolete by 1785).^[3]
• 1780 – verb, to treat with a flux.^[3]

Meanings

Noun

1. Continuous change; instability, especially in a state of flux: The rules for the competition are still in flux.^[13][4][11]
2. A flow or discharge; the action of flowing.^[13][11][3]
3. A substance such as borax used to help metals melt and fuse, to clean surfaces in soldering, or to make enamel and glass fusible.^[13][4]
4. (physics) The rate of flow of a fluid, energy or particles across a given area.^[13][4]
5. (archaic) An abnormal discharge from the bowels; diarrhoea or dysentery.^[11][4][3]

Verb

1. To make fluid or melt; to fuse.^[11][4][3]
2. To treat with a flux: Flux the copper joint before soldering it.^[11][4][3]
3. To flow copiously.^[3][4]

Word family

• fluxgate
• flux density

Related words

• fluxion
• fluctuant
• fluent
• fluid
• fluctuate
• influx
• efflux
• reflux
• flush
• affluent
• superfluous
• fluvial
• mellifluous
• influence

References

1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
3. ^ a b c d e f g h i j k l m n o p q r s t u v w x Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
4. ^ a b c d e f g h i j k l m n o p Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
5. ^ a b c d Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
6. ^ a b Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
7. ^ a b c Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
8. ^ a b The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
9. ^ a b Ayto, John (2005), Word Origins: The Secret Histories of English Words from A to Z, 2nd ed., London: A & C Black
10. ^ Anglo-Norman Dictionary (AND2), Aberystwyth University, anglo-norman.net (2nd ed., 2005–)
11. ^ a b c d e f Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
12. ^ Barnhart, Robert K., ed. (1995), The Barnhart Concise Dictionary of Etymology, New York: HarperCollins
13. ^ a b c d e Collins English Dictionary (2023), Glasgow: HarperCollins
14. ^ Green, Jonathon (2010), Green's Dictionary of Slang, London: Chambers; digital ed. 2016–, https://greensdictofslang.com