Definitions for board foot
Random House Webster's College Dictionary
the basic unit of board measure, equal to the cubic contents of a piece of lumber one foot square and one inch thick.
Category: Building Trades
Ref: Abbr.: bd. ft.
Origin of board foot:
the volume of a piece of wood 1 foot square and 1 inch thick
A board one square foot by one inch, about 2.36 liters.