A candlestick on a price chart indicates the open, high, low, and close prices of an asset over a specific time frame. It visually represents the market sentiment during that period, with the body showing the price range between the open and close. A green or white candlestick signifies a bullish trend (closing price higher than opening), while red or black denotes a bearish trend (closing price lower than opening). Candlesticks provide valuable insights into price movements, trends, and potential reversals, making them essential tools for technical analysis in financial markets.