rod (unit)

A pole (more commonly called a perch or a rod) is a unit of length, equal to 5.5 yards or 16.5 feet (5.0292 metres in SI units). The length is equal to the standardized length of the ox-goad used by medieval English ploughmen; fields were measured in acres which were one chain (four rods) by one furlong (in England, ten chains). Because the furlong was "One Plough's Furrow Long" and a furrow was the length a plough team was to be driven without resting, the length of the furlong and the acre vary regionally, nominally due to differing soil types. In England the acre was 4,840 square yards, but in Scotland it was 6,150 square yards and in Ireland 7,840 square yards. In all three countries, fields were divided in acres and thus the furlong became a measure commonly used in horse racing, archery, and civic planning. The rod is still in use as a unit of measure in recreational canoeing. In particular, canoeing maps measure portages (overland paths where canoes must be carried) in rods. This is thought to persist due to the rod approximating the length of a typical canoe. The lengths of the perch and chain were standardized in 1607 by Edmund Gunter.

Rod (Unit)

See also