1) A wooden structure used as a support for boards, usually in pairs.
1396 unum par tristelles, Hedon
1410 de ij tabulis mensalibus et j pari tristellorum, York
1503 tabulas meas mensales cum le trestels, Ripon
1588 two litle trestles, Dalton
1694 2 tressells for the brickmakers, Tong
1698 for makeing ladders and thristles, Pickering. The use of trestles in bridge building is first noted in 1796 and their function was defined in detail by Smiles in 1861. They formed a part of the complicated timber-work which supported the arch. A reference in the accounts for Kirkstall Bridge in 1616 implies that the trestles were a fundamental part of the centres, if not the centres themselves:For tymber for makinge the trysletes of the arch Ł20For leadinge of this tymber over the value of the tymber when it hathe served for Set the Arch upon Ł5For workinge of this tymber and settinge in the Ryver Ł25In 1699, 5 Trissels and 55 Tressel feet were part of a Frame for turning the Arch on Tadcaster Bridge.