A momentum indicator is a technical analysis tool used to measure the rate at which the price of a security is changing. It compares the current price of an asset to its price at a previous point in time, typically over a specified period. This comparison helps traders and investors gauge the strength and direction of price movements. Momentum indicators are often used to identify potential trend reversals, confirm the strength of an existing trend, or generate buy and sell signals. Examples of popular momentum indicators include the Relative Strength Index (RSI), Moving Average Convergence Divergence (MACD), and Stochastic Oscillator.