From Traderpedia

Definition: Decline in trading capital as a result of losses.

The magnitude of a decline in account value, either in percentage or dollar terms, as measured from peak to subsequent trough. For example, if a trader's account increased in value from $10,000 to $20,000, then dropped to $15,000, then increased again to $25,000, that trader would have had a maximum drawdown of $5,000 (incurred when the account declined from $20,000 to $15,000) even though that trader's account was never in a loss position from inception.

[edit] See also

• Blowout
• Did my arse