Haha, yeah, it's an adjustable spanner wrench first made popular by the Crescent Tool Company back in the 50's and 60's. It was a tool that kept you from having to buy 26 different Open-end (spanner) wrenches, so a heck of a lot of them were sold. They had their name in big letters on the handle, so everybody ended up asking for the "crescent" wrench. Kind of like asking for Channel Locks; Their real name is tongue and groove pliers, but the First Baptist Church of the High and Mightier thought that it was too nasty sounding.
And now you know the rest of the story.
Good Day
Tom