undulation

American  

[uhn-juh-ley-shuhn, uhn-dyuh-, -duh-] / ˌʌn dʒəˈleɪ ʃən, ˌʌn dyə-, -də- /

noun

1. an act of undulating; a wavelike motion.

2. a wavy form or outline.

3. one of a series of wavelike bends, curves, or elevations.

4. Physics.

   1. a wave.

   2. the motion of waves.

---

undulation British  

/ ˌʌndjʊˈleɪʃən /

noun

1. the act or an instance of undulating

2. any wave or wavelike form, line, etc

---

Etymology

Origin of undulation

First recorded in 1640–50; undul(ate) + -ation

Explanation

Undulation is a flowing, up-and-down movement like the motion of waves. Have you ever looked out over the ocean and watched the water flow up and down in waves? If so, you watched undulation, which is exactly that type of movement. Undulation best applies to waves, but it can also describe similar movements. If dancers are moving in a flowing manner, that's also undulation. The verb form of this word is undulate, and both come from the Latin word for "wave," unda.

Example Sentences

Her boss' stiff façade slips as his spine and joints move in a constant state of undulation.

From Salon • Jan. 18, 2025

The team didn’t see telltale signs of lateral undulation, the kind of movement that would indicate swimming played a prominent role in the evolutionary loss of limbs.

From Science Magazine • Sep. 26, 2023

Unlike in skeletal muscles, in the cell membrane of the heart muscle are finger-like discs that conduct the undulation required for pumping.

From Science Daily • Sep. 22, 2023

That 6-1 stretch they had in late May was immediately followed by a 1-5 skid, an undulation pattern that has become all too familiar.

From Seattle Times • Jul. 2, 2023

He could feel the pulse and undulation of those great waves of magic, surging inside the child, never finding their way to shore.

From "The Girl Who Drank the Moon" by Kelly Barnhill