Moderator Post (s) for this thread: >More info neededbydoug seibert on 11/23/2005
Interesting question! Many construction materials are sold or measured in a quantity refered to as Linear Feet. The "Linear" part refers to the length of whatever it is, whether it is a roll of fabric, gutters, trim, rope, chain, cable, etc. The "Feet" part is exactly what you think it is: 12 inches.
Sometimes you will see an estimated quantity of something like painting window trim, and that will sometimes be quoted in lf, or linear feet, and this is arrived at by measuring the perimeter of the window frame and any other parts to be painted. So, a single pane window with no grid that is 2' x 2' would estimate at 4 lf.
You also see the term "board-foot" which is a unit of measurement related to the number of cubic inches in a board. The key to figuring out bd ft is to remember that 1 bd ft equals 144 cubic inches. Any dimension lumber when figuring the thickness by the width by a length that will give you a total of 144 equals one bd ft. For example, a 2"x6"x12" equals one board ft. 2 times 6 equals 12, times 12 equals 144, there by equaling one bd ft.
There is a wonderful board foot explaination at this website: http://www.villagewoodsmith.com/page20.html