verb fluc·tu·ate \ ˈflək-chə-ˌwāt , -chü-ˌāt \
Updated on: 10 Feb 2018

Definition of fluctuate

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


play \ˌflək-chə-ˈwā-shən, -chü-ˈā-\ noun


play \ˌflək-chə-ˈwā-shnəl, -shə-nᵊl, -chü-ˈā-\ adjective

Examples of fluctuate in a Sentence

  1. His popularity has fluctuated during his term in office.

  2. In the desert, the temperature fluctuates dramatically.

Recent Examples of fluctuate from the Web

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.

Origin and Etymology of fluctuate

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

Synonym Discussion of 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

FLUCTUATE Defined for English Language Learners



Definition of fluctuate for English Language Learners

  • : to change level, strength, or value frequently

FLUCTUATE Defined for Kids


verb fluc·tu·ate \ ˈflək-chə-ˌwāt \

Definition of fluctuate for Students

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

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