fluctuation

WordReference Random House Learner's Dictionary of American English © 2025

fluc•tu•ate /ˈflʌktʃuˌeɪt/   v. [no object] , -at•ed, -at•ing. 

1. to change continually; vary irregularly;
   shift back and forth or up and down:
   Prices fluctuated wildly.

fluc•tu•a•tion /ˌflʌktʃuˈeɪʃən/  n. [countable] See -flu-.

WordReference Random House Unabridged Dictionary of American English © 2025

fluc•tu•a•tion  (fluk′cho̅o̅ ā′shən), n. 

1. continual change from one point or condition to another.
2. wavelike motion;
   undulation.
3. Genetics a body variation due to environmental factors and not inherited.

• Latin fluctuātiōn- (stem of fluctuātiō) a fluctuation, wavering. See fluctuate, -ion
• late Middle English 1400–50

WordReference Random House Unabridged Dictionary of American English © 2025

fluc•tu•ate  (fluk′cho̅o̅ āt′), v., -at•ed, -at•ing. 
v.i. 

1. to change continually;
   shift back and forth;
   vary irregularly:
   The price of gold fluctuated wildly last month.
2. to move back and forth in waves.

v.t. 

3. to cause to fluctuate.

• Latin fluctuātus undulated, past participle of fluctuāre to flow, equivalent. to fluctu(s) a flowing (derivative of fluere to flow) + -ātus -ate¹
• 1625–35

Synonyms

• 1. See waver. 
• 2. oscillate.

Collins Concise English Dictionary © HarperCollins Publishers::

fluctuation / ˌflʌktjʊˈeɪʃən/ noun

1. constant change; vacillation; instability
2. undulation
3. a variation in an animal or plant that is determined by environment rather than heredity