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

After a buzz saw of a third quarter that left the American Airlines Center crowd stunned and a near disaster down the stretch, the Celtics escaped with a 106-99 victory over the Mavericks in Game 3 of the NBA Finals on Wednesday to move to the cusp of their first championship since 2008. —Ben Golliver, Washington Post, 13 June 2024

So who is this frighteningly competent Gen Z-Alpha cusp envoy sent to steal all of the YA jobs in Hollywood? —Rachel Handler, Vulture, 15 May 2024

Being the cusp of summer in Nashville, one of those gently emphatic storms rolled through — patient downpours for hours, steady and in no rush to leave. —Ryan Leas, SPIN, 6 June 2024

Fortune’s very first issue, published in February of 1930, came on the cusp of the Great Depression. —Alan Murray, Fortune, 26 Apr. 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