Day order

An order to buy or sell a security valid only for a limited period, normally less than a day.

A day order is an instruction you give to your broker to buy or sell a security at the market price or at a particular price you name before the end of the trading day. The order expires if it isn't filled.

In contrast, a good 'til canceled (GTC) order remains open on the broker's books until it's filled, you cancel it, or the brokerage firm's time limit for GTCs expires.