hydraulics

Etymology

It is from English the plural of hydraulic, used on the model of earlier names of sciences in -ic;^[2][3] compare -ics.^[3][4][5] The adjective is from Latin hydraulicus,^[2][6][7] from Ancient Greek ὑδραυλικός (hudraulikós),^[2][6][7] formed from ὕδωρ (húdōr, “water”) and αὐλός (aulós, “pipe, flute”).^[2][6][7] The Greek adjective was used above all of the ὕδραυλις (húdraulis, “water organ”), a musical instrument worked by water;^[2][6][3] the extension to other water engines came later.^[2]

Earliest recorded meaning

The branch of science that deals with the conveying of water and other liquids through pipes and channels, and with their use as a source of power: 1671, in Robert Boyle.^[2][8] Etymonline dates the word to the 1670s,^[3] and Dictionary.com to 1665–75.^[5]

Semantic evolution

Hydraulics named a branch of engineering from the start, the practical science of water in motion.^[3][2] The adjective hydraulic had come earlier, from 1626 in the OED.^[2] In modern use the word covers the practical application of any liquid in motion, such as the transmission of energy,^[8] and Collins treats it as another name for fluid mechanics.^[9] In 1990s British rhyming slang hydraulics rhymed with ballocks and meant nonsense.^[10]

Timeline

• 1671 – the science of conveying water through pipes and channels and of its use in machines.^[2][8]
• 1998 – British rhyming slang, nonsense.^[10]

Meanings

Noun

1. The branch of science and engineering that deals with the practical uses of water or other liquids in motion, such as the transmission of energy through pipes; used with a singular verb: Hydraulics is a core subject in civil engineering.^[8][9][2]
2. Fluid mechanics.^[9]

Related words

• hydraulic
• hydro-
• water
• hydrant
• hydrate

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h i j k Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d e Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
4. ^ Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
5. ^ a b Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
6. ^ a b c d The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
7. ^ a b c Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
8. ^ a b c d Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
9. ^ a b c Collins English Dictionary (2023), Glasgow: HarperCollins
10. ^ a b Green, Jonathon (2010), Green's Dictionary of Slang, London: Chambers; digital ed. 2016–, https://greensdictofslang.com