cusp

noun

ˈkəsp 

: 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

cuspate

ˈkə-ˌspāt 

-spət

adjective

cusped

ˈkəspt 

adjective

Illustration of cusp

• 1 cusp d

Synonyms

• brink
• edge
• point
• threshold
• verge

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

The zodiac sign on the cusp of your seventh house (along with its planetary ruler) can tell you more about your relationship dynamics and the kind of energy that best aligns with your style of commitment. —Valerie Mesa, People.com, 28 Dec. 2024

With a climax set around a massive New Year’s Eve party in downtown Los Angeles, the film is set on the cusp of the year 2000, then five years away. —Mark Olsen, Los Angeles Times, 27 Dec. 2024

Shore was able to rise to the cusp of reaching the UFC’s Top 15 but couldn’t get over the hump after an excellent run on the independent circuit that earned him a shot with the world’s top promotion. —Brian Mazique, Forbes, 12 Dec. 2024

This year, an abundance of mainstream holiday books feature diverse LGBTQ+ people just on the cusp of falling in love before New Year’s. —Melissa Kravitz Hoeffner, Vulture, 10 Dec. 2024

Word History

Etymology

Latin cuspis point

First Known Use

1585, in the meaning defined above

Phrases Containing cusp

• on the cusp

Kids Definition

cusp

noun

ˈkəsp 

: a point or pointed end or part: as

a

: either of the pointed ends of a crescent moon

b

: a point on the grinding surface of a tooth

c

: a fold or flap of a heart valve

Medical Definition

cusp

noun

ˈkəsp 

1

: a point on the grinding surface of a tooth

2

: a fold or flap of a cardiac valve

cuspal

ˈkəs-pəl 

adjective