Dekameter
A dekameter (dam) is a unit of length in the metric system, equal to 10 meters. It sits between a meter and a hectometer in size. Although it is an official part of the metric system, the dekameter is rarely used in everyday life, education, or even science. For example, a small swimming pool might be around 2 dekameters long. The symbol for dekameter is "dam". Since most people prefer using meters or kilometers, the dekameter is more of a theoretical unit used mainly for teaching the structure of the metric system.
Rod
A rod is a traditional unit of length used in land measurement and surveying. It is equal to 16.5 feet, 5.5 yards, or exactly 5.0292 meters.
Also known as a pole or perch, the rod dates back to medieval England and was commonly used for measuring land and agricultural plots. It is closely related to other units such as the chain (which is 4 rods) and the furlong (which is 40 rods).
Key conversions:
1 rod = 16.5 feet
1 rod = 5.5 yards
1 rod = 5.0292 meters
4 rods = 1 chain
40 rods = 1 furlong
Though largely replaced by metric units today, the rod is still occasionally used in surveying and legal descriptions of land, especially in the United States and the UK.