beach

[16] 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 [14]), on the grounds that the new meaning could have developed from the notion of the ‘pebbly bed of a stream’. => BECK

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   The word did not appear generally in English until the 16th century. It was originally a dialect term for shingle or pebbles on the seashore. When Shakespeare uses the word, it is not clear whether he meant the general sense or the specific: 'You may as well go stand upon the beach' (The Merchant of Venice). The word itself may relate to Old English bæce, 'stream' (modern beck).