Lumber, also known as Timber, is wood that has been processed into beams and planks, a stage in the process of wood production.
Lumber may be supplied either rough-sawn, or surfaced on one or more of its faces.
A plank is timber that is flat, elongated, and rectangular with parallel faces that are higher and longer than wide. Used primarily in carpentry, cabinet making (cabinetry and furniture), wood carving, joinery, carpentry, and woodturning.
Planks also serve as supports to form shelves and tables.