incisor

Etymology

It is borrowed from Medieval Latin incīsor (“a cutter; a cutting tooth”),^[2][3][4][5] found in the phrase dens incisor (“incisor tooth”).^[6] Merriam-Webster Unabridged and Dictionary.com instead class it as New Latin,^[7][8] the former from a Late Latin word for one that cuts.^[7] It is an agent noun from incīdō (“to cut into, cut open, engrave”),^[2][3] through the past participle incīsus,^[3][4][7] and the verb is formed from in- (“into”) and caedō (“to cut”),^[3] from Proto-Indo-European *kae-id- (“to strike”).^[3] Middle English had the plural inscisours, a surgical instrument shaped somewhat like shears, recorded before 1425, which the Middle English Dictionary derives from Medieval Latin incīsōrium under the influence of scissor.^[9][3]

Earliest recorded meaning

A tooth adapted for cutting: Merriam-Webster Unabridged gives 1666,^[7] Etymonline the 1670s,^[3] and the OED's first quotation is from before 1682, in Sir T. Browne's A Letter to a Friend.^[2]

Semantic evolution

The word has kept its literal sense, "that which cuts into".^[3][4] Johnson (1755) defined it as "Cutter; tooth in the forepart of the mouth."^[10] From 1830, in Donovan's Domestic Economy, it is also used attributively, both for what is adapted for cutting (incisor forceps) and for what is connected with these teeth (incisor artery).^[2] The fuller form incisor tooth is still used.^[6][11]

Timeline

• 1666 – a tooth adapted for cutting.^[7] The OED's first quotation is from before 1682.^[2]
• 1830 – attributive, adapted for cutting, or connected with these teeth.^[2]

Meanings

Noun

1. A narrow-edged tooth at the front of the mouth, used for cutting or gnawing; humans have four in each jaw.^[12][13][6]
2. In mammals, a cutting tooth rooted in the premaxillary bone of the upper jaw ahead of any canines, or the matching tooth of the lower jaw.^[7]

Related words

• incise
• incision
• incisive

References

1. ^ 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 e f g h Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
4. ^ a b c Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
5. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
6. ^ a b c Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
7. ^ a b c d e f Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
8. ^ Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
9. ^ Kurath, Hans; Kuhn, Sherman M.; Lewis, Robert E., eds. (1952–2001), Middle English Dictionary, Ann Arbor: University of Michigan Press; online edition ed. Frances McSparran et al. (2000–2018)
10. ^ Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
11. ^ Stedman's Medical Dictionary, Baltimore: Lippincott Williams & Wilkins
12. ^ Collins English Dictionary (2023), Glasgow: HarperCollins
13. ^ The American Heritage Dictionary of the English Language (2000), 4th ed., Boston: Houghton Mifflin