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

This material offers superior protection against moisture, temperature fluctuations, and humidity changes, ensuring a stable environment for your gown. —Shelby Wax, Vogue, 22 May 2025

Despite the market fluctuations, data shows that sales volume for properties priced above $1 million through April reached $2.5 billion in 2025, slightly up from $2.4 billion in 2024 but still down from $2.8 billion in 2022. —Sara B. Hansen, Denver Post, 22 May 2025

For example, connected aircraft engines can transmit continuous operational data, allowing engineers to analyze vibration patterns, temperature fluctuations and pressure differentials to forecast potential issues. —Ajay Parihar, Forbes.com, 21 May 2025

That said, President Donald Trump’s tariff policies are a major factor in the fall and fluctuation of the U.S. Dollar Index, which had tumbled to 97.9 in late April—the lowest in slightly more than three years. —Allison Landa, Travel + Leisure, 21 May 2025

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