A form of stop-loss designed to keep profit coming (or prevent loss) as the price of a stock remains moving in an investor’s favor. Generally opened at the same time as a trade, a long position would put a trailing stop-loss at a price lower than the current market price and for a short position, it would be placed above the market price. They only move in one direction and are designed to lock in profit and protect from (or limit) loss.
We don't know everything about the markets. We're just devoted to learners. Taken from those smarter than ourselves, here's how we define Trailing Stop-Loss.