noun
volatility; rate of fluctuation; degree of variability
Technical term used in finance, statistics, and engineering to describe how much a value changes over time. The gloss 'regulation' is rare and may appear in older or specific technical contexts.
この株の変動率は非常に高い。
The volatility of this stock is very high.
為替レートの変動率を計算する。
Calculate the rate of fluctuation of the exchange rate.
ボラティリティ is the direct loanword for 'volatility' and is very common in financial contexts, often used interchangeably with 変動率.
Compound of 変動 (fluctuation) and 率 (rate).