A stop-limit order is an order that becomes a limit order when it hits the stop price. The stop price is set above the current market price for a buy order or below the current market price for a sell order. Once the stop price is hit, the order turns into a limit order and is filled at the limit price or better. For example, if you enter a buy stop-limit order at $5.00 with a stop price of $5.25 and a limit price of $5.50, your order will become a $5.50 limit order when the stock reaches your stop price of $5.25. A stop-limit order gives you more control over the price at which your purchase is executed than a typical stop order does.
The same logic applies to cryptocurrencies: replace stock with cryptocurrency.