A perch is a unit of length that was historically used in some English-speaking countries, primarily in the United Kingdom. It is equivalent to 5.5 yards or 16.5 feet (about 5.0292 meters). The term "perch" is relatively old and is not commonly used in modern measurements.
Perches were often used in land measurement, particularly in agriculture and real estate. They were also sometimes used in surveying. However, the use of the perch as a standard unit of measurement has largely been replaced by more modern and standardized systems such as the metric system or the imperial system based on feet and yards. As a result, the perch is considered an archaic or historical unit of measurement today.
A chain is a unit of length used in some older systems of measurement, particularly in surveying and land measurement. In the United States, one chain is equal to 66 feet or 22 yards. Internationally, it's defined as exactly 20.1168 meters.
Chains were historically used for measuring large plots of land and for surveying purposes, often in agriculture and real estate. However, the use of the chain as a standard unit of measurement has largely been replaced by the more modern and standardized metric and imperial systems, which use units like meters, feet, and yards.
The term "chain" comes from the practice of physically measuring land using a chain made of linked metal bars or wire. Each chain was typically 66 feet long, and surveyors would lay out chains end to end to measure distances across large areas. Today, modern surveying equipment such as electronic distance measuring devices (EDMs) and GPS technology have largely replaced the use of physical chains in land surveying.