Definition
A unit of measure for lumber equal to the volume of a piece of wood that is 12 inches long, 12 inches wide, and 1 inch thick — a total of 144 cubic inches.
Plain English
A standard amount of wood used to measure how much lumber you have. One board-foot is a square piece of wood, one foot on each side and one inch thick.
Context Anchor
Seen in wood aircraft construction, repair, and material ordering when lumber quantity is measured by volume.
Derivation
“Board-foot” combines “board,” meaning a flat piece of cut wood, with “foot,” the 12-inch unit of length. Together they name a standard amount of board material, based on a one-foot by one-foot board that is one inch thick.
Why Pilots Care
Wooden aircraft and many homebuilt designs use lumber specified by board-foot. Knowing the unit lets a builder or mechanic order the right amount of wood for repairs or construction.
Analogy
Think of it like a standard measuring block for lumber. The board can have different actual dimensions, but if its wood volume equals 12 inches by 12 inches by 1 inch, it equals one board-foot.
Intuition Check
Do not read “board-foot” as the length of a board. It is a volume measure for wood: length times width times thickness.
Example Sentence 1
The wing repair required twelve board-feet of aircraft-grade spruce.
Example Sentence 2
Ordering stock for the fuselage frame, the builder asked for forty board-feet total.