A stop-loss is a risk management discipline, not a CSE order type in the traditional sense. It is a price level you define in advance at which you will exit a position to prevent further losses. Once the stock trades at or below that price, you sell (either automatically via a standing broker instruction or manually when you notice the trigger has been hit).
The primary purpose of a stop-loss is psychological discipline — it removes the emotional decision-making that leads many investors to "hold and hope" as a position declines, often resulting in much larger losses than were necessary.
Stop-loss levels are typically set as a percentage below the purchase price (e.g., 10% below cost) or below a meaningful technical support level. The appropriate level depends on the investor's risk tolerance, the volatility of the stock, and the size of the position relative to the overall portfolio.
On the CSE, liquidity constraints are relevant. For illiquid stocks, a stop-loss may not execute near the intended price if a material seller hits the market suddenly. This "gap risk" is a key reason to avoid concentrated positions in low-liquidity names.