Lumber (also known as timber) is wood in any of its stages from felling to readiness for use as structural material for construction, or wood pulp for paper production.

Lumber is supplied either rough or finished. Besides pulpwood, rough lumber is the raw material for furniture-making and other items requiring additional cutting and shaping. It is available in many species, usually hardwoods, but it is also readily available in softwoods such as white pine and red pine due to their low cost per board foot.^{[citation needed]} Finished lumber is supplied in standard sizes, mostly for the construction industry, primarily softwood from coniferous species including pine, fir and spruce (collectively known as Spruce-pine-fir), cedar, and hemlock, but also some hardwood, for high-grade flooring.