noun
seat (horizontal part of a chair)
Refers specifically to the flat horizontal board that forms the sitting surface of a chair or bench.
この椅子の座板は硬くて、長時間座ると痛い。
The seat of this chair is hard, and it hurts if you sit for a long time.
noun
Used for a single board that forms part of a floor; compare with 床板 (ゆかいた), which is more common for floorboards in general.
See also: 床板
古い家の座板がきしむ音がする。
The floorboards in the old house creak.