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

• change
• flux
• inconstancy
• oscillation

Examples of fluctuation in a Sentence

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

Recent Examples on the Web

It is designed to alleviate the side effects of hormonal fluctuations and to prevent weight gain, according to US News. —Melissa Rudy, Fox News, 10 Jan. 2025

But, consistency at the position is where there’s been much fluctuation. —Audrey Snyder, The Athletic, 6 Jan. 2025

Between night sweats, sugar cravings, and hormonal fluctuations, Perimenopause significantly affected my skin. —Shalwah Evans, People.com, 5 Jan. 2025

Among the concerns: The technology to match hydrogen production with hourly fluctuations in wind and solar power is still in its infancy. —Brad Plumer, New York Times, 3 Jan. 2025

Word History

First Known Use

15th century, in the meaning defined above

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