beach:  Beach is a mystery word. When it first turns up, in the dialect of the southeast corner of England, it means ‘shingle’; and since long stretches of the seashore in Sussex and Kent are pebbly, it is a natural extension that the word for ‘shingle’ should come to be used for ‘shore’. Its ultimate source is obscure, but some etymologists have suggested a connection with Old English bæce or bece ‘stream’ (a relative of English beck ), on the grounds that the new meaning could have developed from the notion of the ‘pebbly bed of a stream’. => beck
1530s, "loose, water-worn pebbles of the seashore," probably from Old English bæce, 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.