Rugby terminology isn't as standarized as their gridiron counterparts, at least partially because the game is so much more free-flowing. Different teams will use different names for similar "plays", at least in part because you have to shout them out in the course of play (no huddles) and you don't want to make it too easy for the opposition to read what is coming. The play you ask about is a fairly common attacking pattern coming off a quick ball -- a flyhalf/first receiver supported by two outside backs. The flyhalf calls the play, and the outside back switches to an inside line while the inside man wraps behind to an outside line. I've hear it called various things; a slash, a wrap, and I remember that one team called it a "rangy". No idea why. The flyhalf will decide which player the pass goes to depending on how the defense reacts to the situation. He may even opt not to pass at all if neither defender commits to him.
