Surfboard is a modern English compound of surf (a 17th-century word of obscure origin, perhaps from suff, an Indian-coast term for the sea swell) and board (from Old English bord 'plank'). The historical chain includes Old English bord. The quoted older sense, "plank," supplies the immediate semantic anchor for surfboard. The formation is best read as compound: the word surfboard carries its older form-history into a compact English lexical shape. In present English it is used as a noun, "a long narrow board used for riding ocean waves". Related English forms include surf, surfer, and board. The result is a noun whose etymology preserves both the older form and the later English specialization.