cusp

Etymology

It is borrowed from Latin cuspis (“point, spear, pointed end, head”),^{[2][3][4][5][6]} which is of unknown or uncertain origin.^[3][4][7][8] The Latin word is also the source of cuspid, bicuspid and tricuspid,^[7] and of cuspidate.^[5]

Earliest recorded meaning

In astrology, the beginning or entrance of a "house", a division of the heavens: 1579, in Thomas Lupton's Thousand Notable Things.^[2][9] Barnhart dates it to 1585,^[4] and Etymonline to the 1580s.^[3]

Semantic evolution

The general sense of a point or apex, or a pointed ornament, is recorded from 1647, in Henry More.^[2][4][6] In astronomy, from 1676, in a letter of Halley, the word named each horn of the crescent moon, or of Mercury and Venus, or of the partly eclipsed sun;^[2][3] Johnson (1755) knew only this use, a term for the points or horns of the moon or another luminary.^[10] Geometry took it up in 1758 for the point where two branches of a curve meet with a common tangent,^[2][6] architecture in 1813 for the points between the foils of Gothic tracery,^[2][6] anatomy in 1849 for a point on the crown of a tooth^[2] (Etymonline dates this sense to 1839)^[3] and later for the flaps of the heart valves,^[2][11] and botany in 1870 for the sharp point of a leaf.^[2] The figurative sense, a point of transition between two states, usually in on the cusp of, is recorded from 1908.^[2] The Oxford Dictionary of Word Origins thinks it probably comes from the astrological use for the division between one sign and the next.^[12]

Timeline

• 1579 – in astrology, the beginning of a house.^[2][9]
• 1647 – a point, apex or pointed ornament.^[2][4]
• 1676 – each horn of the crescent moon.^[2][3]
• 1694 – top, surface (now obsolete).^[2]
• 1758 – in geometry, a point where two branches of a curve meet.^[2][6]
• 1813 – in architecture, a point between the foils of Gothic tracery.^[2][6]
• 1849 – a point on the crown of a tooth.^[2]
• 1870 – in botany, a sharp, rigid point of a leaf.^[2]
• 1879 – a pointed flap, as of a heart valve.^[2]
• 1908 – figurative, a point of transition; a verge.^[2]

Meanings

Noun

1. A point of transition between two periods or states; a verge or threshold, usually in on the cusp of: The band was on the cusp of fame.^[9][2]
2. A point or pointed end; an apex or peak.^[11][9][2]
3. One of the raised points on the chewing surface of a tooth.^[11][2]
4. One of the triangular flaps of a heart valve.^[11][2]
5. In geometry, a point at which two branches of a curve meet with a common tangent.^[11][9][2]
6. In architecture, a projecting point between the small arcs or foils in Gothic tracery.^[11][2][6]
7. In astronomy, either horn of a crescent moon or of a planet in a similar phase.^[11][9][2]
8. In astrology, the beginning of a house, or the division between two houses or signs.^[11][9][2]
9. In botany, a sharp, rigid point, as at the tip of a leaf.^[2][6]

Word family

• cuspate
• cusped
• cuspal

Related words

• bicuspid
• cuspid
• tricuspid
• cuspidate

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 28 29 Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d e f Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
4. ^ a b c d e Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
5. ^ a b Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
6. ^ a b c d e f g h Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
7. ^ a b Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
8. ^ Partridge, Eric (1966), Origins: A Short Etymological Dictionary of Modern English, 4th ed., London: Routledge & Kegan Paul
9. ^ a b c d e f g Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
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. ^ a b c d e f g h Collins English Dictionary (2023), Glasgow: HarperCollins
12. ^ Cresswell, Julia (2021), Oxford Dictionary of Word Origins, 3rd ed., Oxford: Oxford University Press