capacitor

Etymology

It is formed from English capacity + -or,^[2][3][4][5] the agent-noun ending added to capacity in its electrical sense.^[6] Capacity itself is from Old French capacité, from Latin capācitās (“capacity, ability to hold much”), from capāx (“able to hold much”), from capiō (“to take”), from Proto-Indo-European *kap- (“to grasp”).^[6]

Earliest recorded meaning

A device that stores electricity during part of an operation, the same as a condenser: 1926, in a British Standard glossary of electrical engineering terms.^[2] Etymonline also dates it to 1926,^[6] while Merriam-Webster gives 1925 as the first known use,^[3] and Dictionary.com 1925–30.^[5]

Semantic evolution

The word builds on the sense of capacity "power to store electricity", recorded from 1777,^[6] and on capacitance, the ability to store an electric charge, from 1893.^[6] It took over from condenser, which had been used for an apparatus that accumulates an electric charge since 1782, in Volta;^[2] the OED notes that condenser in this sense is now largely superseded by capacitor,^[2] and Collins gives condenser as its former name.^[7]

Timeline

• 1777 – capacity in the sense "power to store electricity".^[6]
• 1926 – capacitor, a device that stores electric charge; a condenser.^[2][6] Merriam-Webster dates it to 1925.^[3]

Meanings

Noun

1. An electrical component that stores electric charge, usually made of two conducting plates or foils separated by a dielectric such as air or mica; formerly called a condenser: The old radio hummed until the technician replaced a leaking capacitor.^[7][3][8][2]

Related words

• capacitance
• capacity
• condenser
• capable
• capacious

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
4. ^ Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
5. ^ a b Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
6. ^ a b c d e f g Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
7. ^ a b Collins English Dictionary (2023), Glasgow: HarperCollins
8. ^ Webster's New World College Dictionary (2014), 5th ed., Boston: Houghton Mifflin Harcourt