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.
His popularity will likely fluctuate as people respond to his policies and national and international events. Kate Plummer, MSNBC Newsweek, 17 Oct. 2025 The pay package, which fluctuates in value based on the stock price and is currently worth more than $100 billion, was put to an advisory vote last year. Kara Carlson, Fortune, 17 Oct. 2025 The numbers fluctuate over the years, but, as a broad trend, the improvement in pass completion and the number of passes made per game over the past decade was accompanied by a significant rise in goals scored and, in particular, the proportion of goals scored from open play. Oliver Kay, New York Times, 16 Oct. 2025 In interviews, including with Variety’s Marc Malkin, Johnson explained that his fluctuating appearance was preparation for his next movie. Angelique Jackson, Variety, 16 Oct. 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 18 Oct. 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

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!