Historical Volatility
https://www.investopedia.com/terms/h/historicalvolatility.asp
Historical volatility (HV) is a statistical measure of the dispersion of returns
for a given security or market index over a given period of time. This measure is calculated by determining the average deviation
from the average price
of a financial instrument in the given time period. Using standard deviation to calculate historical volatility. The higher the historical volatility value, the riskier the security.
https://www.fool.com/knowledge-center/how-to-calculate-annualized-volatility.aspx