Length of a furrow in a field of the kind ploughed by a team of eight oxen. It was 40 perches or 220 yards in length. This made one part of the measure of an acre, the other being 22 yards in width. This was the area of land deemed ploughable by a team in one day. The Latin term used in *DB is quarentina = 40. [< OldEngl. furh = furrow + lang = long] -
Dictionary of Medieval Terms and Phrases. Christopher Coredon with Ann Williams.