The process whereby sand and shingle move along a beach shoreline when waves approach the shore at an angle(noun)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "longshore drift" in a sentence
"A fixed line drawn eastwest from A to B kept on intersecting different parts of the restless island from year to year in response to the longshore drift and other currents, freighted with pebbles, tugging at the island this way and that."