1530s, "loose, water-worn pebbles of the seashore," probably from a dialectal survival of Old English bece, bece "stream," from Proto-Germanic *bakiz. Extended to loose, pebbly shores (1590s), and in dialect around Sussex and Kent beach still has the meaning "pebbles worn by the waves." French grève shows the same evolution. Beach ball first recorded 1940; beach bum first recorded 1950.
"to haul or run up on a beach," 1814, from beach (n.). Related: Beached; beaching.