The word cord probably comes from the amount of cord or string it takes to tie this bundle of wood. It’s been a semi-offiical measurement since at least 1610.
One full cord: A full cord is a large amount of wood. It measures four feet high by four feet wide by eight feet long (4 ft. x 4 ft. x 8 ft.) and has a volume of 128 cubic feet. The amount of solid wood in a cord varies depending on the size of the pieces, but for firewood it averages about 85 cubic feet.
Maine is unusual. It also defines a “loose thrown cord” or pile of cut firewood as “A cord of 12 or 16 inches (30 or 41 cm) in length shall mean the amount of wood, bark and air contained in a space of 180 cubic feet (5.1 m3); and a cord of wood 24 inches (61 cm) in length shall mean the amount of wood, bark and air contained in a space of 195 cubic feet (5.5 m3).
One Face cord: This commonly consists of wood that is 16 inches long. The volume of a face cord therefore is 1/3 of the volume of a full cord even though it is 8 feet long and 4 feet high. A face cord is also called a “Rick of Wood “in the mid-western United States.