The teaspoon is a unit of volume in the US customary system and uses the symbol Tsp.
In the kitchen, the teaspoon is the smaller of the commonly used spoons served at the table and represents 1/6 US fluid ounce, 1/48 US cup or, expressed in SI / metric format; 4.92892159375 ml.
A teaspoon is generally considered a cooking measure but is also used in the administration of medicine when in solution form; 5 ml or multiples thereof is the standard amount of liquid medicine across the world.
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.