Round Lot - An order to buy or sell in multiples of 100 shares.

Odd Lot - An order to buy or sell that involves less than 100 shares.

Market Order - An order to buy or sell at the best price currently available.

Limit Order - An order to buy or sell when and if a security reaches a specific price.

Good Til Cancelled (GTC) Order - An order to buy or sell at a specific price until the investor cancels the order.

Scale Order - An order to buy or sell a security that specifies the total amount to be bought or sold at specified price variations.

Stop Order - An order to buy at a price above or sell at a price below the current market. Stop buy orders are generally used to limit or protect unrealized profits on a short sale. Stop sell orders are generally used to protect unrealized profits or limit loss on a holding. A stop order becomes a market order when the stock sells at or beyond the specified price and, thus, may not necessarily be executed at that price.