A chain can be any of the following:
- a flexible connection through multiple rigid links; applications include:
- pulling (it can not be used for pushing)
- keeping together to avoid falling apart, drifting away, theft, fleeing (of a prisoner)
- In mathematics
- a measure of length used in surveying and equal to 22 yards (also called the surveyor's or Gunter's chain);
- a measuring instrument used in engineering, also called the engineer's or Ramsden's chain (and rarely, its length of 100 ft as a unit of measurement, though the results of the measurements are normally expressed in feet); or
- a franchise of stores, restaurants, hotels, or other retail establishments.
- a type of armor made of interlocking chain links, better known as chainmail.
See also Chain of command.