A pin bar is a candlestick chart pattern that indicates a possible trend reversal. It consists of a small real body (usually white or black) with upper and lower shadows, which resemble the shape of a flagpole or pennant. The name "pin bar" comes from the fact that it looks like a vertical line has been "pinned" onto the chart, marking a potential turning point in the market's direction. Traders often use this pattern as a signal to enter trades in the opposite direction of the prevailing trend.