fluctuation
UK: ˌflʌk.tʃuˈeɪ.ʃən | US: ˌflʌk.tʃuˈeɪ.ʃən
n. an irregular rising and falling in number or amount; a variation
n. (physics) a random deviation in a quantity from its mean value
n. (general) continuous change or instability
The word traces back to Latin fluctuatio, derived from fluctus (wave), reflecting the idea of movement like waves—rising and falling unpredictably. Over time, it broadened to describe any irregular variation, whether in physical quantities (e.g., prices, temperatures) or abstract concepts (e.g., emotions). The root fluere also gives us "fluid" and "influence," emphasizing the theme of flow and change.
The stock market showed significant fluctuation this week.
Temperature fluctuations made it hard to predict the weather.
Her mood fluctuations were noticeable after the stressful event.
Scientists measured minor fluctuations in gravitational waves.
The artist embraced the fluctuation of light in her paintings.