fluctuate

verb

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

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

Synonyms of fluctuate

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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.
Studying the effects of this fluctuating luminescence on interpreting gesture may tell us whether speech has significant benefits around an evening campfire. — Mike McRae 02, New Atlas, 3 Sep. 2026 The principal of individual TIPS can fluctuate over their term based on inflation. — Darla Mercado, Cfp®, CNBC, 2 Sep. 2026 Estrogen can fluctuate significantly during the menopausal transition, and those changes can affect far more than the reproductive system. — Dr. Jessica Shepherd, Flow Space, 1 Sep. 2026 As Hafley and Sullivan have continued to emphasize, the rookies’ play will likely fluctuate throughout the regular season. — Miami Herald, 1 Sep. 2026 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

Rhymes for fluctuate

See All Rhymes for fluctuate

Browse Nearby Words

fluctuant
fluctuate
fluctuating
See all Nearby Words

Cite this Entry

“Fluctuate.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/fluctuate. Accessed 4 Sep. 2026.

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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
ˌflək-chə-ˈwā-shən How to pronounce fluctuate (audio)
noun
Last Updated: - Updated example sentences
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