A bullish hammer candlestick pattern is a single-candle reversal signal that typically forms at the bottom of a downtrend, indicating potential trend reversal. It has a small real body near the top of the candle, a long lower shadow at least twice the length of the body, and little to no upper shadow. The long lower wick shows that sellers initially pushed prices down strongly, but buyers stepped in and regained control, driving the price back near the opening level. This shift in momentum signals that selling pressure is weakening and buying interest is emerging, making it a potential entry signal for traders when confirmed by higher volume or a subsequent bullish candle.