From AMS Glossary
(Also called littoral current.) The resultant current produced by waves being deflected at an angle by the shore.
In this case the current runs roughly parallel to the shoreline. The longshore current is capable of carrying a certain amount of material as long as its velocity remains fairly constant; however, any obstruction, such as a submarine rock ridge or a land point cutting across the path of the current, will cause loss of velocity and consequent loss of carrying power.