A market order is a type of trade order to buy or sell a financial instrument immediately at the current best available price. It guarantees that the order will be executed quickly but does not guarantee the price at which the trade will occur. Market orders are typically used by traders who prioritize the execution of the trade over the price, such as when entering or exiting a position quickly during volatile market conditions. However, in fast-moving markets, the final execution price may differ from the last quoted price due to slippage.