What does NIN stand for on naruto path of the ninja 2?

If u go into the game then push start then go to Ninja Tag u will see NIN at the bottom of the stats wat does it mean?|||it mean how much room it will take so u cant equip something that is over your NIN|||NIN means ninja in the naruto: path of the NINJA 2|||Watch over 550 Anime Series online for FREE! at http://tinyurl.com/54x2lh|||I think it stands for Nine Inch Nails.