# smoothness

> English word · Noun · frequency rank #35,084

## Definitions
1. The condition of being smooth; the degree or measure of said condition.
2. The highest order of derivative (the differentiability class) over a given domain.
3. The quantity measured by the modulus of smoothness.

## Etymology
From Middle English smothenesse; equivalent to smooth + -ness. Compare Old English smēþnes (“smoothness, a smooth place, a level surface”).

## Common misspellings (14)
`msoothness`, `smmoothness`, `smoohtness`, `smoothenss`, `smoothhness`, `smoothnes`, `smoothnness`, `smoothnses`, `smootnhess`, `smootthness`, `smothness`, `smotohness`, `somothness`, `ssmoothness`

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