|≈||approximately equal to|
|digits||indicates that digits repeat infinitely (e.g. 8.294 369 corresponds to 8.294 369 369 369 369 …)|
The board-foot is a specialized unit of measure for the volume of lumber in the United States and Canada. It is the volume of a one-foot length of a board one foot wide and one inch thick.
Board-foot can be abbreviated FBM (for "foot, board measure"), BDFT, or BF. Thousand board-feet can be abbreviated as MFBM, MBFT, or MBF. Similarly, million board-feet can be abbreviated as MMFBM, MMBFT, or MMBF.
The ale or beer firkin (from Middle Dutch vierdekijn meaning "fourth") is a quarter of an ale or beer barrel or half a kilderkin. This unit is much smaller than the wine firkin. Casks in this size (themselves called firkins) are the most common container for cask ale.