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

Dabo Swinney’s team, which handled The Citadel 51-14, should move to the cusp of the top 12 on Tuesday heading into a home showdown with current No. 18 South Carolina (8-3). —Stewart Mandel, The Athletic, 24 Nov. 2024

The Cincinnati Bearcats open the season in the top 25 and the Xavier Musketeers are right on the cusp of being ranked. —Jason Hoffman, The Enquirer, 1 Nov. 2024

In a 24-hour span last month, the Aggies went from the cusp of winning the College World Series to wondering how the Longhorns hired Schlossnagle so quickly. —Mitch Sherman, The Athletic, 10 July 2024

Our nation is at the cusp of a historic opportunity: Finally rebuilding the domestic steel industry, growing jobs, and nurturing stronger communities after decades of neglecting our critical supply chains. —David McCall, Fortune, 4 Oct. 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