fluctuate

verb

fluc·​tu·​ate ˈflək-chə-ˌwāt How to pronounce fluctuate (audio)
-chü-ˌāt
fluctuated; fluctuating

intransitive verb

1
: to shift back and forth uncertainly
Oil prices fluctuated.
Temperatures fluctuated.
2
: to rise and fall in or as if in waves
The boat fluctuated on the rough sea.

transitive verb

: to cause to fluctuate
Choose the Right Synonym for fluctuate

swing, sway, oscillate, vibrate, fluctuate, waver, undulate mean to move from one direction to its opposite.

swing implies a movement of something attached at one end or one side.

the door suddenly swung open

sway implies a slow swinging or teetering movement.

trees swaying in the breeze

oscillate stresses a usually regular alternation of direction.

an oscillating fan

vibrate suggests the rapid oscillation of an elastic body under stress or impact.

the vibrating strings of a piano

fluctuate suggests constant irregular changes of level, intensity, or value.

fluctuating interest rates

waver stresses irregular motion suggestive of reeling or tottering.

the exhausted runner wavered before collapsing

undulate suggests a gentle wavelike motion.

an undulating sea of grass

Examples of fluctuate in a Sentence

His popularity has fluctuated during his term in office. In the desert, the temperature fluctuates dramatically.
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
But fuel surcharges levied on all of these package delivery methods can fluctuate from week to week. Jason D. Greenblatt, MSNBC Newsweek, 2 Apr. 2025 The lake is fed from both cold and hot underground springs, and the water fluctuates from about 73 to 77 degrees in the winter up to about 91 to 97 degrees in the summer. Maggie Fuller, AFAR Media, 1 Apr. 2025 Gas prices: Five straight days of increases at the pumps The average price of gas has fluctuated quite a bit in 2025. Washington Examiner Staff, The Washington Examiner, 31 Mar. 2025 The forfeiture was included in the indictment filed against Madigan in March 2022, however the numbers have fluctuated slightly as the evidence was presented. Ray Long, Chicago Tribune, 31 Mar. 2025 See All Example Sentences for fluctuate

Word History

Etymology

Latin fluctuatus, past participle of fluctuare, from fluctus flow, wave, from fluere — more at fluid

First Known Use

1604, in the meaning defined at intransitive sense 2

Time Traveler
The first known use of fluctuate was in 1604

Browse Nearby Words

Cite this Entry

“Fluctuate.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/fluctuate. Accessed 9 Apr. 2025.

Kids Definition

fluctuate

verb
fluc·​tu·​ate ˈflək-chə-ˌwāt How to pronounce fluctuate (audio)
fluctuated; fluctuating
1
: to move up and down or back and forth like a wave
2
: to be constantly changing especially up and down
fluctuation noun

More from Merriam-Webster on fluctuate

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