Drawdown
A drawdown is a fall from a peak, measured in percent: how much of the value at the top has been lost at the lowest point that follows.
Recovering from a drawdown takes a bigger percentage rise than the fall itself. After a 50% drawdown you need +100% to get back; after Bitcoin’s 77.6% fall from 69,000 in November 2021 to 15,476 in November 2022, it needed +346% to return to 69,000. On a log chart the fall and the rise that repairs it are drawn at the same height.
Learn more: linear or log chart.