crankshaft

Etymology

It is formed from English crank + shaft.^[2][3][4] Etymonline takes the first part as the verb crank,^[2] Dictionary.com as the noun.^[3] The word was also written with a hyphen.^[2][4]

Earliest recorded meaning

A shaft turned by a crank: 1803, according to Etymonline.^[2] The OED's first quotation, for a shaft driven by a crank, is from 1854, in Ronalds and Richardson's translation of Knapp's Chemical Technology,^[4] and Merriam-Webster also dates the word to 1854;^[5][6] Dictionary.com gives 1850–55.^[3]

Semantic evolution

The word first named any shaft driven by a crank or driving one.^[2][4][5] It also came to mean the shaft made of a series of cranks and crankpins to which the connecting rods of an engine are attached.^[5][6] Etymonline notes that the basic mechanism appears to go back to Roman times.^[2]

Timeline

• 1803 – a shaft turned by a crank.^[2] The OED and Merriam-Webster date it to 1854.^[4][5]

Meanings

Noun

1. A shaft that is driven by a crank or that drives one.^[5][6][7][4]
2. A shaft made up of a series of cranks and crankpins, to which the connecting rods of an engine are attached: The mechanic found a crack in the crankshaft.^[5][6]

Related words

• crank
• shaft
• crankcase

References

1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
3. ^ a b c Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
4. ^ a b c d e f Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
5. ^ a b c d e f Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
6. ^ a b c d Merriam-Webster's Collegiate Dictionary (2003), 11th ed., Springfield, Mass.: Merriam-Webster
7. ^ The American Heritage Dictionary of the English Language (1992), 3rd ed., Boston: Houghton Mifflin