roof boards; ceiling boards
Refers to the boards used for roofing or ceiling in traditional Japanese architecture.
back board (of furniture)
The board forming the back panel of a piece of furniture, such as a cabinet or chest.
The back board of this bookshelf is made of thin plywood.
The roof boards of the old house were damaged, so I had a carpenter replace them.
Compound of 裏 (ura, 'back, reverse') and 板 (ita, 'board'). The exact historical derivation is uncertain, but the meaning follows straightforwardly from the components.