viscosity

Etymology

It is inherited from Middle English viscosite,^[2][3][4] borrowed from Old French viscosite (13th century) or directly borrowed from Medieval Latin viscōsitās,^[5][2][4][6] from Late Latin viscōsus (“sticky”), the source of viscous,^[5][4][7] and the suffix -itās.^[3] The adjective is formed from viscum (“birdlime made from mistletoe; mistletoe”),^[5][4] which Etymonline traces probably to Proto-Indo-European *weis- (“to melt away, flow”).^[4] The Anglo-Norman word is recorded from the second quarter of the 13th century,^[8] and the OED compares viscosità, viscosidad and viscosidade.^[5]

Earliest recorded meaning

A glutinous or sticky quality: before 1400, in a Middle English translation of Lanfranc's surgery, which says that every ripening medicine is hot "wiþ a maner viscosite".^[2] The OED's first record is from before 1425, in a translation of John Arderne's treatise on fistula,^[5] and Etymonline dates the word to the late 14th century.^[4]

Semantic evolution

The word began in medical writing for the stickiness of bodily matter and medicines,^[2][5] and since 1540 it could also mean a viscous substance itself.^[5] Johnson (1755) gave both senses, "glutinousness; tenacity" and "a glutinous substance".^[9] In physics it took on the precise sense of a fluid's internal friction, its resistance to a change of shape, in James Clerk Maxwell's paper of 1866;^[5][4] the measure of this became a quantity in its own right,^[10][3] and since 1892 magnetic viscosity was used for the lag of a magnetic material behind the magnetizing force.^[5]

Timeline

• before 1400 – a sticky or glutinous quality.^[2] The OED's first record is from before 1425.^[5]
• 1540 – a viscous substance.^[5]
• 1866 – in physics, the internal friction of a fluid.^[5][4]
• 1892 – magnetic viscosity.^[5]

Meanings

Noun

1. The quality of being viscous, thick and sticky: The viscosity of the syrup made it slow to pour.^[10][3][5]
2. In physics, the resistance of a fluid to flowing, caused by internal friction.^[10][3][5]
3. A measure of this resistance; the coefficient of viscosity.^[10][3]
4. The ability of a solid to keep yielding under shear stress.^[3]
5. A viscous substance.^[3][5]

Word family

• hyperviscosity

Related words

• viscous
• viscid
• viscose

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e 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)
3. ^ a b c d e f g h Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
4. ^ a b c d e f g h Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
5. ^ a b c d e f g h i j k l m n o p Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
6. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
7. ^ Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
8. ^ Anglo-Norman Dictionary (AND2), Aberystwyth University, anglo-norman.net (2nd ed., 2005–)
9. ^ Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
10. ^ a b c d Collins English Dictionary (2023), Glasgow: HarperCollins