fluctuate

verb

fluc·​tu·​ate ˈflək-chə-ˌwāt 

-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

Synonyms of fluctuate

• vary
• change
• shift

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

Applying mulch offers several benefits, including retaining soil moisture, reducing soil erosion, insulating roots from fluctuating soil temperatures, and suppressing weeds. —Lauren David, Southern Living, 17 Apr. 2026

However, gold doesn’t generate income like stocks or bonds, and its price can fluctuate in the short term. —Jessica Walrack, USA Today, 16 Apr. 2026

While other atmospheric features can vary or fluctuate in latitude over time, this hexagonal feature is remarkably constant, changing by only negligible amounts in terms of its distance from the pole. —Big Think, 15 Apr. 2026

LeVota said in his Tuesday video statement that spreading tax credits out over three years, rather than recouping one lump sum from school districts, was the county’s attempt to mitigate the impact of fluctuating property tax values. —Ilana Arougheti, Kansas City Star, 15 Apr. 2026

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

Rhymes for fluctuate

• abdicate
• abrogate
• acetate
• activate
• actuate
• adsorbate
• aggravate
• agitate
• alginate
• alienate
• allocate
• amputate

Kids Definition

fluctuate

verb

fluc·​tu·​ate ˈflək-chə-ˌwāt 

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 

noun