# undulation

> English word · Noun

## Definitions
1. An instance or act of undulating.
2. A wavy appearance or outline; waviness.
3. A tremulous tone produced by a peculiar pressure of the finger on a string.
4. A wavelike curve; a smooth and regular rise and fall.
5. A wavelike motion of the air; electromagnetic radiation.
6. A feeling as if of an undulatory motion about the heart.
7. The distinctive motion of the matter within an abscess on being pressed when it is ripe for opening.

## Etymology
From undulate + -ion, or borrowed from Medieval Latin undulātiō; compare French ondulation.

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