In the game of golf, if the first swing's not your thing, you might take a mulligan. But how did this redo shot get its name? WFMZ's Joscelyn Moes finds out in the U.S. Women's Open edition of her series "Why Do They Call It That?"

>> REPORTER: Hitting the pristine green at Center Valley Club is a favorite past-time for many folks.

>> JOHN LIBRICK: It's something that you can do till you're 90 years old.

>> REPORTER: But some do it better than others. So when you've not got the shot..

>> JOHN LIBRICK: When you go out to the course if you hit a bad shot somebody's say hey I'm gonna take my mulligan now.

>> REPORTER: Mulligans are not allowed in tournament golf, but socially why not?

>> JIM DOMINICK: I have 18 mulligans when I play, so I have unlimited mulligans.

>> PHIL PETERSON: Do you use them? If the group I'm with will allow them absolutely. And as you can tell by the guy before me, we're using them. Today he'll use 18.. I'll use maybe 3 or 4.

>> REPORTER: Being the golf pro that I am, I took a shot at using one, or several. But what's the driving force behind the name mulligan?

>> PHIL PETERSON: Perhaps an old Irish man in Ireland started using them a lot and they named it after Mulligan.

>> REPORTER: Close. While there are many theories, most involve Canadian golfer David Mulligan. One popular story is while Mulligan was playing at the Country Club of Montreal in the 1920s, he hit a poor tee shot, re-teed and shot again. Mulligan called it a "correction shot," but his friends thought it deserved a better name, so they called it a "mulligan."

So the next time you can't bring your swing, mull over a do-over. And why do they call it a Mulligan? Now you know.