TSA pre-check is a pre-screening program that air travelers can use to bypass the normal security line.
It's not a huge time-saver (any more, used to be more) but gets you out of a few annoyances like removing shoes, unpacking toiletries, and a few other things. And the lines are usually a bit shorter and the ratio of regular traveller to new traveller is a bit better (less likely to get caught behind somebody who doesn't know the process and wastes everybody's time).
