Good Through
An order to buy or sell a security or commodity at a certain price for a certain period of time, unless it is canceled or changed.
Investopedia Commentary
Good through is a type of limit order that can be set as GTW (Good-This-Week), GTM (Good-This-Month), or for any other specified period of time.
Related Links
Understanding Order Execution
The Basics Of Order Entry
See also: Good 'till Canceled - GTC, Good This Month - GTM, Limit Order