fluctuation

noun

fluc·​tu·​a·​tion ˌflək-chə-ˈwā-shən 

-chü-ˈā-

plural fluctuations

: an act or instance of fluctuating : an irregular shifting back and forth or up and down in the level, strength, or value of something

Small fluctuations in prices are to be expected.

Some fluctuation in real estate values is not unusual.

North American species in general, having contended with blazing July days and frosty September nights as they evolved, are much more tolerant of temperature fluctuations than tropical species are.

—Jonathan Franzen

fluctuational

ˌflək-chə-ˈwā-sh(ə-)nəl 

-chü-ˈā-

adjective

Synonyms of fluctuation

• oscillation
• change

Examples of fluctuation in a Sentence

political instability that resulted in wild fluctuations in the overseas stock markets

Recent Examples on the Web

The decrease in approvals for citizenship comes amid fluctuations in those applying to naturalize. —Ximena Bustillo, NPR, 13 Apr. 2026

Over time, your photos may show signs of these temperature fluctuations via discoloring, yellowing, fading, or even sticking together. —Kate Van Pelt, The Spruce, 13 Apr. 2026

This strategy allows investors to smooth the impact of interest rate fluctuations over time. —Michelle Fox, CNBC, 13 Apr. 2026

Internal consumer research conducted by Squared Circles suggests that many women experience only around 10 truly optimal days a month due to natural hormonal fluctuations, yet are expected to perform consistently across work, training, relationships and life. —Kathryn Hopkins, Footwear News, 13 Apr. 2026

Word History

First Known Use

15th century, in the meaning defined above

Rhymes for fluctuation

• abdication
• aberration
• abjuration
• abnegation
• abrogation
• acceptation
• acclamation
• acclimation
• accusation
• activation
• actuation
• acylation

Medical Definition

fluctuation

noun

fluc·​tu·​a·​tion ˌflək-chə-ˈwā-shən 

1

: a motion like that of waves

especially : the wavelike motion of a fluid collected in a natural or artificial cavity of the body observed by palpation or percussion

2

a

: a slight and nonheritable variation

especially : such a variation occurring in response to environmental factors

b

: recurrent and often more or less cyclic alteration (as of form, size, or color of a bodily part)

fluctuate

ˈflək-chə-ˌwāt 

verb

fluctuated; fluctuating