fulcrum

Etymology

It is borrowed from Latin fulcrum (“head or back support of a couch, bedpost”),^[2][3][4][5] from fulciō (“to prop up, support”)^[2][3][6] and the noun suffix -crum.^[2] Dictionary.com sees in it an older Latin fulctrum, with the suffix of instrument -trum.^[7] In post-classical Latin the noun also meant a support or prop in general and help or assistance, from the 4th century,^[2] and it was later applied to parts of plants, fishes and insects, senses that English took over.^[2][8] The OED calls the verb of uncertain origin and only perhaps related to balk;^[2] Etymonline and Klein are firmer, deriving it from Proto-Indo-European *bhelg- (“beam, plank”), the source of balk,^[3][9] and Klein adds Ancient Greek φάλαγξ (phálanx, “trunk, log; line of battle”).^[9] Compare French fulcre, now obsolete, and Italian fulcro.^[2]

Earliest recorded meaning

A prop or support: 1659, in Gayton's Art of Longevity.^[2] Other dictionaries give later dates: Merriam-Webster Unabridged 1668,^[8] Etymonline the 1670s,^[3] and Barnhart 1674.^[4]

Semantic evolution

A word for part of a couch came into English in the general sense of a prop, and the Oxford Dictionary of English says that was its original use.^[10] It then narrowed to the point on which a lever turns or against which it is set; the OED now treats the general sense as obsolete, though Merriam-Webster Unabridged and Collins still list it.^{[2][11][8][12]} A figurative use, for the person or point on which something crucially depends, is as old as 1668, in Howe.^[2] From the 18th century it was also a term of natural history, for small parts of plants (1754) and scales on the fins of fishes (1771), and later for structures in insects (1825), trilobites (1847) and rotifers (1855).^[2] The verb is much later, from 1870, and was first transitive; "to turn on a pivot" appears in 1904.^[2]

Timeline

• 1659 – a prop or support; later, the point on which a lever turns.^[2]
• 1668 – figurative, a crucial point or person on which something depends.^[2]
• 1754 – botany, an accessory organ of a plant, such as a stipule or tendril.^[2]
• 1771 – a small bony scale on the fins of certain fishes.^[2]
• 1825 – a structure in insects supporting the pharynx.^[2]
• 1870 – verb, to provide with a fulcrum.^[2]
• 1904 – verb, to turn as if on a pivot.^[2]

Meanings

Noun

1. The support or point on which a lever turns or rests: Move the fulcrum nearer the load and the bar lifts it more easily.^[12][8][2]
2. A prop or support in general.^[12][8]
3. A person or thing on which an activity or situation crucially depends: The treaty was the fulcrum of her foreign policy.^[10][2][8]
4. (zoology) One of the small spinelike scales along the front edge of the fins in some primitive bony fishes.^[12][8][2]
5. (entomology) A hard structure that supports the pharynx or the male genitals in certain insects.^[2]
6. (botany, rare) An accessory organ of a plant, such as a bract or tendril.^[2]

Verb

1. To furnish with a fulcrum, or to make a fulcrum of.^[8][2]
2. To turn as if on a pivot, usually with on.^[2]

Related words

• balk
• phalanx

Usage notes

The plural is fulcrums or fulcra.^[12][8] The OED notes that /ʌ/ in the first syllable was the usual pronunciation until the mid-20th century.^[2]

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 r s t u v w x y z 27 Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
4. ^ a b Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
5. ^ The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
6. ^ Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
7. ^ Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
8. ^ a b c d e f g h i Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
9. ^ a b Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
10. ^ a b Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
11. ^ Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
12. ^ a b c d e Collins English Dictionary (2023), Glasgow: HarperCollins