The “Free RN” part means the shoe is part of the Free line of shoes, and is for running (RN), instead of just general training.The “Motion” part in the name means this shoe has a web of triangular pods on the sole, instead of the standard grid of shapes on other free shoes.This triangular web gives the shoe a bit more flexibility/motion over the standard free sole. Finally, “Flyknit” is in the name of the shoe, which is Nike’s flexible cloth upper.