Running english
Side spin on the cue ball that causes it to roll off a cushion (contacted at an angle) with rather than against the ball's natural momentum and direction of travel.[6] If angling into a rail that is on the right, then running english would be left english, and vice versa. The angle of deflection will be wider than if no english were applied to the cue ball. But more importantly, because the ball is rolling instead of sliding against the rail, the angle will be more consistent. For this reason, running english is routinely used. Also called running side in British terminology. Contrast reverse english.
quote from
http://www.answers.com/topic/glossary-of-cue-sports-terms#R