When investors give up any previous gains in stock price by selling equities in an effort to get out of the market and into less risky investments. True capitulation involves extremely high volume and sharp declines. It usually is indicated by panic selling.
The term is a derived from a military term which refers to surrender.
Source:
https://www.investopedia.com/terms/c/capitulation.asp
See also:
https://www.investopedia.com/ask/answers/189.asp
