Board foot
Primary source
Verbatim text below is from the Electronic Code of Federal Regulations (eCFR), a public-domain U.S. government work. Always verify the current version with the eCFR before relying on it for any legal matter.
Full Text
Board foot or BF means a unit of measurement of softwood lumber represented by a board 12-inches long, 12-inches wide, and 1-inch thick or its cubic equivalent. A board foot calculation for softwood lumber 1 inch or more in thickness is based on its nominal thickness and width and the actual length. Softwood lumber with a nominal thickness of less than 1 inch is calculated as 1 inch.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.