Design Specification.

Been looking all around the net for help, thought I would come back to good ol' sythe.org

Can some one please explain to me what "User, Form and function" means when referring to Design Specification. If it helps im designing a media/theater room I have the compulsory and optional sub sections but was not show or told what user, form or function is supposed to mean/do...

Ohh to add on to this, the theme we are looking at is pimp my ride so I don't know if its got something to do with how its found, working ect.