Volatility

Formal

Specifically relating to share prices, this is the speed of change in a share price measured over a period of time. Also refers to the general market uncertainty where investors are unsure about the prospects of economies or vertical business sectors.

Real-world Example

A tech stock's price swings 10% up or down within a single week, while a utility stock barely moves - the tech stock has much higher volatility, reflecting greater uncertainty and risk.