pronation: stick your (right handed is assumed) racquet hand in front of you in a thumbs up,( thumb pointing stright up), now point your thumb to your left, the act of turning your hand inwards like this is called pronating.The word pronation describes the act of pronating. supination: stick your (right handed is assumed) racquet hand in front of you in a thumbs up,( thumb pointing stright up), now point your thumb to your right, turning your hand outwards like this is called supination.The word supination describes the act of supinating. linear take back/smile takeback/U takeback : they mean the same thing, it's when you take the racquet straight back and up, like this arrow goes the other way though as I'm talking about the takeback c backswing, loopy backswing: C stands for circular, take the racquet back and trace a loop in the air. Heavy Ball: A ball that feels heavy on your racquet, it feels as if your hitting a very heavy object (,like a bowling ball or a brick), be it flat as a pancake like agassi's backhand or hit with heavy topspin like Nadal's forehand. A ball that has lots of topspin and bounces around the height of your shoulders but does not feel heavy on your racquet is NOT a heavy ball.A ball with so called 'Heavy' topspin and a loopy trajectory isn't a heavy ball unless it feels heavy on your racquet.So called 'Heavy' topspin is a characteristic of many genuinely heavy balls, but does not itself qualify a ball as heavy, only a heavy sensation felt by the reciever when trying to return it does. that's all I can think of for now, this thread is for technical terms and jargon only.