A limit order is an order placed with a brokerage to execute a buy or sell transaction at a set number of shares and at a specified limit price or better. It is a take-profit order placed with a bank or brokerage to buy or sell a set amount of a financial instrument at a specified price or better; because a limit order is not a market order, it may not be executed if the price set by the investor cannot be met during the period of time in which the order is left open. Limit orders also allow an investor to limit the length of time an order can be outstanding before being canceled.

Source : Investopedia