wooden board; plank
Refers to a piece of wood cut into a flat, rectangular shape, used in construction, woodworking, etc.
この板材は厚さが2センチある。
This wooden board is 2 centimeters thick.
I bought some planks at the home improvement store.
Compound of 板 (ita, 'board') and 材 (zai, 'material, lumber').