# cusp

> English word · Noun · IPA /kʌsp/ · frequency rank #27,112

## Definitions
1. A sharp point or pointed end.
2. An important moment when a decision is made that will determine future events.
3. A point of a curve where the curve is continuous but has no derivative, but such that it has a derivative at every nearby point.
4. A point made by the intersection of two curved lines or curved structures, a common motif in Gothic architecture.
5. A boundary between zodiacal signs and houses.
6. Any of the pointed parts of a canine tooth or molar.
7. A flap of a valve of a heart or blood vessel.
8. A point of transition.

## Etymology
From Latin cuspis (“a point, spear, pointed end”); first used in astrology. Doublet of cuspid and cuspis.

## Easily confused with
- **cut** (https://plainspell.com/en/vs/cusp-vs-cut)
- **cuz** (https://plainspell.com/en/vs/cusp-vs-cuz)
- **CVS** (https://plainspell.com/en/vs/cusp-vs-cvs)
- **cute** (https://plainspell.com/en/vs/cusp-vs-cute)
- **cuts** (https://plainspell.com/en/vs/cusp-vs-cuts)
- **cyst** (https://plainspell.com/en/vs/cusp-vs-cyst)
- **cuss** (https://plainspell.com/en/vs/cusp-vs-cuss)
- **cs** (https://plainspell.com/en/vs/cs-vs-cusp)
- **cp** (https://plainspell.com/en/vs/cp-vs-cusp)
- **CU** (https://plainspell.com/en/vs/cu-vs-cusp)
- **cup** (https://plainspell.com/en/vs/cup-vs-cusp)
- **cap** (https://plainspell.com/en/vs/cap-vs-cusp)
- **cop** (https://plainspell.com/en/vs/cop-vs-cusp)
- **CBS** (https://plainspell.com/en/vs/cbs-vs-cusp)
- **cos** (https://plainspell.com/en/vs/cos-vs-cusp)
- **cum** (https://plainspell.com/en/vs/cum-vs-cusp)
- **cue** (https://plainspell.com/en/vs/cue-vs-cusp)
- **CDs** (https://plainspell.com/en/vs/cds-vs-cusp)
- **cis** (https://plainspell.com/en/vs/cis-vs-cusp)
- **cas** (https://plainspell.com/en/vs/cas-vs-cusp)

## Common misspellings (5)
`ccusp`, `csup`, `cuspp`, `cussp`, `ucsp`

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/cusp