buoyancy

Etymology

It is formed from English buoyant + -ancy.^[2][3][4] Etymonline and Merriam-Webster take the suffix as -cy.^[5][6] Buoyant (1578) is perhaps from Spanish boyante, present participle of boyar (“to float”), from boya (“buoy”),^[2][5][7][6] or Old French bouyant;^[2][3][8] the Spanish noun goes back to the source of buoy.^[5][7] The rarer form buoyance was made from buoyancy on the pattern of pairs such as elegancy and elegance.^[6]

Earliest recorded meaning

The power of floating: 1713, in W. Derham's Physico-Theology.^[2][6][5] Johnson (1755) quotes the same work for "the quality of floating": "All the winged tribes owe their flight and buoyancy to it."^[4]

Semantic evolution

From the tendency of a body to float, the word passed in hydrostatics to the upward pressure that a liquid exerts on a body in it, equal to the weight of the liquid displaced (1791).^[2][3] As a property of the liquid itself, the power to support a floating body, it is recorded from 1868 in the OED,^[2] and Etymonline dates this meaning to 1831.^[5] The figurative sense, lightness of spirit and the ability to recover after a setback, appeared in 1819, in Blackwood's Edinburgh Magazine,^[2][5] following the figurative use of buoyant from about 1661.^[2] From 1883 it was used in finance of prices or revenue that tend to rise or hold up.^[2]

Timeline

• 1713 – the power of floating.^[2][5][6]
• 1791 – in hydrostatics, the upward pressure of a liquid on a body in it.^[2]
• 1819 – figurative, lightness of spirit, resilience.^[2][5]
• 1868 – of a liquid, the power of supporting a floating body.^[2] Etymonline dates this meaning to 1831.^[5]
• 1883 – a tendency of prices or revenue to rise.^[2]

Meanings

Noun

1. The ability to float on a liquid or to rise in a fluid.^[9][6][2]
2. The upward force that a fluid exerts on a body wholly or partly submerged in it.^[9][6][3]
3. The ability to recover quickly from setbacks; resilience or cheerfulness: the buoyancy of her mood after the exam.^[9][2]
4. A tendency of prices, markets or revenue to rise or stay high.^[2]

Related words

• buoyant
• buoy

References

1. ^ 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 Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ 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
4. ^ a b Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
5. ^ a b c d e f g h i Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
6. ^ a b c d e f g Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
7. ^ a b The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
8. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
9. ^ a b c Collins English Dictionary (2023), Glasgow: HarperCollins