1. Literally, to be in the process of leaving or about to leave some place. I'm actually on the way out just now, so we'll have to leave the meeting until tomorrow. The doctor rang just as we were on the way out the door.

2. To be decreasing in use or popularity; to be in the process of becoming obsolete or nonexistent. Based on the low number of viewers it's had this season, this show is on the way out.