\ˈkəsp \

Definition of cusp 

: point, apex: such as

a : a point of transition (as from one historical period to the next) : turning point also : edge, verge on the cusp of stardom … you're on the cusp between heat exhaustion and life-threatening heatstroke. — Mark Jannot

b : either horn of a crescent moon

c : a fixed point on a mathematical curve at which a point tracing the curve would exactly reverse its direction of motion

d : an ornamental pointed projection formed by or arising from the intersection of two arcs or foils (see foil entry 2 sense 4)

e(1) : a point on the grinding surface of a tooth

(2) : a fold or flap of a cardiac valve

Illustration of cusp

Illustration of cusp

1 cusp d

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Other Words from cusp

cuspate \ˈkə-​ˌspāt, -​spət \ adjective
cusped \ˈkəspt \ adjective

Synonyms for cusp


apex, end, nib, nose, pike, point, tip

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Examples of cusp in a Sentence

the cusp of a tooth medical researchers who are on the cusp of a major breakthrough

Recent Examples on the Web

Congress is on the cusp of passing a bill that could authorize hundreds of thousands of self-driving cars without traditional controls like steering wheels and pedals to be deployed as taxis or sold as personal vehicles. Andrew J. Hawkins, The Verge, "Riding in Waymo One, the Google spinoff’s first self-driving taxi service," 5 Dec. 2018 Sure, the Cubs and Astros each won a World Series after blowing it up, and teams such as the Braves and Phillies seem to be on the cusp of big things. Matt Calkins, The Seattle Times, "Mariners have torn their core asunder, but will it lead to a bright future?," 4 Dec. 2018 Rapidly rotating Wolf-Rayet stars are thought to give rise to long gamma ray bursts, in part because the heat of the core and their rapid rotation leave them on the cusp of bursting apart. John Timmer, Ars Technica, "Scientists spot two massive stars creating a pinwheel of dust," 20 Nov. 2018 Now, Democrats are on the cusp of reversing the trend. Aaron Zitner, WSJ, "Why House Votes and Political Power Often Don’t Match," 16 Nov. 2018 On the cusp of fashion fame, the determined beauty wasn’t about to let anything stop her. Janelle Okwodu, Vogue, "How a Farm Girl From Sweden Became One of the Season’s Biggest Models," 25 Oct. 2018 Entering his third season with the Indiana Pacers, the former Michigan Wolverine was on the cusp of firmly establishing himself as a solid rotation player in the NBA. Vince Ellis, Detroit Free Press, "Detroit Pistons Glenn Robinson III coming for starting forward spot," 14 July 2018 Now 52 and 53, Patrice and her husband, Dan, are on the cusp of a new life stage — three of their five children are now financially independent young adults, and the two kids at home are just a few years away from graduating high school. Stephanie Walden, USA TODAY, "How to find balance and get your retirement plan back on track," 13 July 2018 To facilitate his son’s racing career, Jones’ late father, Dave, sold a classic 1965 Corvette when his son was on the cusp of becoming a teenager. Edgar Thompson,, "Emotion-filled 22-year-old Erik Jones captures chaotic Coke Zero Sugar 400," 9 July 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'cusp.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of cusp

1585, in the meaning defined above

History and Etymology for cusp

Latin cuspis point

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Statistics for cusp

Last Updated

10 Dec 2018

Look-up Popularity

Time Traveler for cusp

The first known use of cusp was in 1585

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More Definitions for cusp



English Language Learners Definition of cusp

: a pointed end or part where two curves meet


\ˈkəsp \

Kids Definition of cusp

: a point or pointed end the cusp of a tooth


\ˈkəsp \

Medical Definition of cusp 

1 : a point on the grinding surface of a tooth

2 : a fold or flap of a cardiac valve

Other Words from cusp

cuspal \ˈkəs-​pəl \ adjective

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More from Merriam-Webster on cusp

Thesaurus: All synonyms and antonyms for cusp

Spanish Central: Translation of cusp

Nglish: Translation of cusp for Spanish Speakers Encyclopedia article about cusp

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