Chain

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)
  - power transmission, as in roller chains;
  - conveyance systems, similar to a conveyor belt, as in flat chains and pintle chains;
- keeping together to avoid falling apart, drifting away, theft, fleeing (of a prisoner)
- jewellery
a mathematical term used in algebraic topology;
a totally ordered subset of a partially ordered set, used in set theory;
a measure of length within the Imperial system of measurement, the chain equal to 22 yards, formerly used in England and giving rise to
- a customary measurement of length used in surveying, also called the surveyor's or Gunter's chain;
- a customary measurement of length used in engineering, also called the engineer's or Ramsden's chain; or
a franchise of stores or restaurants.