The Momentum Indicator is a technical analysis tool used to measure the rate of change in a security's price over a specific period, helping traders identify the strength of a price trend. Typically calculated by comparing the current price to a previous price, the indicator oscillates around a zero line, with positive values indicating upward momentum and negative values suggesting downward momentum. Traders often use this indicator alongside other tools to confirm trends or identify potential reversals, enhancing their decision-making process in the financial markets.