Limit: A limit order is a buy or sell that you set the desired price and when there is a counterpart willing to buy/sell at the set price, the trade will be executed. Note that this could never be executed or be partly executed.

Market: A market order is a buy or sell order to be executed immediately at the current market prices. As long as there are willing sellers and buyers, market orders are filled. Market orders are used when certainty of execution is a priority over the price of execution.