A pin bar is a single candlestick pattern that signals strong rejection of price at a particular level, often indicating a potential reversal. It has a small real body and a long wick (shadow) on one side, showing that price moved sharply in one direction but was quickly pushed back by buyers or sellers. A long lower wick (bullish pin bar) suggests buyers rejected lower prices and may push the market up, while a long upper wick (bearish pin bar) indicates sellers rejected higher prices and may drive the price down. Pin bars become more reliable when they form at key support/resistance zones, trendlines, or after extended moves, as they reflect a shift in market sentiment.