noun
doubling plate (carpentry); fishplate (railways); attached board
Technical term for a reinforcing or joining plate used in woodworking and railway construction. In carpentry, it refers to a board attached to strengthen a joint; in railways, it is the metal plate connecting rail ends.
梁の継ぎ目に添え板を当てて補強する。
Reinforce the beam joint by applying a doubling plate.
レールの接続部には添え板が使われている。
Fishplates are used at the rail joints.
Compound of 添え (soe, 'attaching') + 板 (ita, 'board'). The exact historical derivation is uncertain, but the term is conventionally associated with its technical meanings in carpentry and railways.