Capitulation
Capitulation is a burst of panic selling, usually on very high volume, where holders give up and sell at heavy losses.
It often marks the late stage of a bear market: a sharp drop, record volume and a rush of forced and emotional selling that leaves few sellers behind. Traders look for it as a sign that the selling is exhausted.
It is easy to name afterwards and hard to spot at the time, since falls that look like capitulation sometimes continue. An oversold RSI and a volume spike are the usual evidence.