"Aln" is a unit of length that is used in some parts of Scandinavia, particularly in Sweden and Norway. The term "aln" is derived from the Old Norse word "alinn," which means "forearm." Historically, it was a common unit of measurement for cloth, textiles, and land.
The exact length of an aln could vary by region, but it was generally around 2 Swedish feet or approximately 59.4 centimeters (or about 23.4 inches) in Sweden. In Norway, an aln was somewhat longer, typically around 62.7 centimeters (about 24.7 inches).
The use of the aln as a standard unit of measurement has largely been replaced by the metric system in Scandinavia and most parts of the world, but it may still be referenced in historical or traditional contexts.
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 However, the use of the chain as a standard unit of measurement has largely been replaced by the more modern and standardized metric and imperial systems, which use units like meters, feet, and yards.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.