What is Time-in-Force for an order?

The two Time-In-Force designations are as follows:

1) Day: A day order will automatically expire at market close (4 PM EST) if not filled intraday.

2) GTC: A good 'til cancelled order will be resubmitted to the market at the beginning of the trading day if not already filled. A GTC order is valid for 90 days (including weekends and holidays) after it is created.