The cubic inch is a unit of volume derived from the imperial unit system and uses the symbol in³.
1 cubic inch is defined as equal to the volume of a cube with edges measuring 1 in. It is equivalent in volume to 16.387 ml, 1/231 US gallons and 1/1728 ft³.
Common uses for cubic inches include quantifying the size of electrical boxes and in the automotive industry for measuring engine displacement. The 5th generation Ford Mustang ran on a Boss 302 which was a 302 in³ engine (5.0L).
The board foot is a unit of volume derived from the imperial system of units with the symbol FBM.
1 board foot is equal to the volume of an object one foot in length, one foot wide and one inch thick. It is therefore equal to 1/12 ft³.
The board foot is the unit used to measure rough or planed lumber. For example 2 x 4 timber when planed actually only measures 1.5 in x 3.5 in. This takes into account the wastage when planing. The board feet measurement in this case would represent the wholesale amount. Where the loss in board feet (and planing) only applies to width and thickness, the actual length is used - as there is no loss when cutting lengths.