The term "pit stop" originates from car racing, but it can also be used as a slang term for going to the restroom. For example, if you're on a long road trip with friends, if you stop at a restaurant, someone might say, "I'm going to run in for a quick pit stop."

It is a reference to motor racing - a "pit stop" is when a car leaves the track part way through a race so that it can be checked before continuing :)

Thank you so much!

In a professional car race, the "pit" is where a driver in the race briefly stops for refueling or some repairs for a matter of seconds before re-entering the race. A crew of people are there to do the quick work or refueling. That's all it is. Once someone in the race drives into the "pit" and stops, we call that a "pit stop." That's where the expression comes from.