Good 'Til Canceled - GTC

What Does Good 'Til Canceled - GTC Mean?
An order to buy or sell a security at a set price that is active until the investor decides to cancel it or the trade is executed. If an order does not have a good-'til-canceled instruction then the order will expire at the end of the trading day the order was placed.

Investopedia explains Good 'Til Canceled - GTC
In most cases, GTC orders are canceled by brokerage firms after 30-90 days. This type of order is traditionally placed at price points away from the price of the stock at the time the order is placed. For example if a stock you hold is currently $40 but you believe it will go to $50 at which point you will sell then, you can use a GTC order. Once the GTC order to sell is placed, if the price of the stock reaches $50 at any point over the next few months your shares will be sold.