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

Definition 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

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Other Words from fluctuate

fluctuation \ ˌflək-​chə-​ˈwā-​shən How to pronounce fluctuation (audio) , -​chü-​ˈā-​ \ noun
fluctuational \ ˌflək-​chə-​ˈwā-​shnəl How to pronounce fluctuational (audio) , -​shə-​nᵊl , -​chü-​ˈā-​ \ adjective

Synonyms & Antonyms for fluctuate


change, mutate, shift, snap, vary


plateau, stabilize

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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

On the night of Florida’s August primary, several malfunctions caused county websites to appear erratically: In Leon County, online precinct results were delayed and then fluctuated wildly. Benjamin Wofford, Vox, "The midterms are already hacked. You just don’t know it yet.," 25 Oct. 2018 Estrogen plays a role in regulating mood, sleep, and your overall sense of well-being, and levels of this hormone start fluctuating during perimenopause. Sarah Richards, Woman's Day, "Quiet Your Mind in Anxious Times With These Expert Tricks," 14 Aug. 2018 Just like a strong wind can create waves in a body of water, fluctuating electric and magnetic fields can cause chorus waves in the plasma near objects like Earth. Chelsea Gohd, Space.com, "Jupiter's Largest Moon Ganymede Produces Powerful Plasma Waves," 8 Aug. 2018 South Korea’s Kospi fell less than 0.1 percent to 2,468.83 after fluctuating earlier in the day. Yuri Kageyama, USA TODAY, "Asian shares higher, Europe mixed after Trump-Kim summit," 12 June 2018 Because of the way computer screens render a display—sending signals to each pixel of each line with varying intensity levels for each sub-pixel—the power sent to each pixel fluctuates as the monitor goes through its refresh scans. Sean Gallagher, Ars Technica, "Researchers find way to spy on remote screens—through the webcam mic," 28 Aug. 2018 Year round, the average temperature fluctuates ever so slightly; from the capital of Cagliari, the winter months average out to 50 degrees and push 80 degrees in summer. Lilah Ramzi, Vogue, "Learning From Sardinia, Where Locals Live La Dolce Vita Longer Than Anyone Else," 16 July 2018 Lots can happen in 35 years: Memories fluctuate, witnesses disappear and, as with any investigation from that time, DNA evidence was neither collected or processed. 2. Christian Boone, ajc, "5 things to know about Spalding County cold case murder trial," 23 June 2018 Fuel surcharges also provide transparency into a fluctuating cost of deliveries. Paul Ziobro, WSJ, "Amazon’s Pitch to Woo Shippers: Fewer Fees Than FedEx, UPS," 23 Jan. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'fluctuate.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of fluctuate

1604, in the meaning defined at intransitive sense 2

History and Etymology for fluctuate

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

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Statistics for fluctuate

Last Updated

6 Apr 2019

Look-up Popularity

Time Traveler for fluctuate

The first known use of fluctuate was in 1604

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More Definitions for fluctuate



English Language Learners Definition of fluctuate

: to change level, strength, or value frequently


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

Kids Definition of fluctuate

: to change continually and especially up and down The temperature fluctuated.

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Comments on fluctuate

What made you want to look up fluctuate? Please tell us where you read or heard it (including the quote, if possible).


an enemy or opponent

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