The Stochastic Oscillator is a momentum indicator used in technical analysis to compare a security's closing price to its price range over a specific period. It helps traders identify overbought or oversold conditions in the market, which can signal potential reversals. The oscillator ranges from 0 to 100, with values above 80 indicating overbought conditions and values below 20 indicating oversold conditions. This tool consists of two lines: %K and %D. The %K line represents the current closing price relative to the price range, while the %D line is a moving average of %K. Traders often look for crossovers between these lines to make buy or sell decisions.