A death cross is a bearish technical signal that occurs when a shorter-term moving average crosses below a longer-term moving average, most commonly the 50-day moving average crossing below the 200-day moving average. It suggests that recent price momentum is weakening relative to the longer-term trend, and historically it has preceded significant market declines. While widely watched, the death cross is a lagging indicator and should be confirmed with other technical signals.
Example
“Bitcoin's 50-day moving average crossed below its 200-day moving average, forming a death cross that triggered a wave of selling from momentum traders.”