Coupling

Coupling is a term that describes the degree to which one module relies on another module for its proper functioning. Coupling is mainly of the following two types:

• Loose coupling: Loose or weak coupling implies that a change in one module does not require changes in the implementation of another module.


• Tight coupling: Tight or strong coupling implies that a module relies on another module so strongly that a small change in one will require an implementation change in the other.
  

For a good object-oriented design, loose coupling is desirable.