1) A pointed blade of grass.
2) A substantial length of timber, usually oak or elm, with the lower end sharpened, sometimes tipped with iron. They were used in the construction of weirs, dams, fish-garths, bridges and the like.
1322 & in pilis pro nouo stagno molendini faciendis, Leeds. Archaeological evidence shows that huge numbers were driven into the bed of a river to support bridge foundations, weirs or water-banks: 1398-9 quod omnes pile, pali et kidelli in aqua de Ouse positi ammoveantur citra festum Pasche, York. In 1422, Thomas Rawson was indicted because he ‘made 1 weyr with pylles … on the north side of the water’, thereby diverting it from its ‘ancient course’, Bradford. Piles are mentioned frequently in Yorkshire bridge documents from the seventeenth century: 1616 For thre hundredth and fortye pyles with leading, workinge and dryveninge we estimate at 3s 4d, Kirkstall
1705 the Pyles … for repair of the Banks and Wears, Bradley. It was used also as a verb: 1682 For wood … to be well piled downe there … and to be Fastned with Coupleing the same … to the old frame, Cottingley.