Over the top is a motion a golfer makes on the downswing where the club path is outside the swing path of the backswing, causing the golfer to swing to the left, resulting in a slide or pull hook.
Similar to coming over the top, an outside-to-in motion occurs when a golfer takes the club away from his body, and returns the club swinging towards the body and left.
An inside-to-out swing is a motion that a golfer creates by taking the club away close to his body, and returning the club swinging the club out towards the right, producing a draw or push-fade.
A two-plane swing occurs when the angle of a golfer's backswing differs from the angle of the downswing. Most golfers, to some degree, have a two-plane swing.
Flat describes the horizontal path the golf club travels throughout the swing.
Steep describes the vertical path the golf club travels throughout the swing.
A shallow golf swing is similar to the term flat that describes the horizontal path the golf club travels throughout the swing.