In telecommunication, coupling is the desirable or undesirable transfer of energy from one medium, such as a metallic wire or an optical fiber, to another like medium, including fortuitous transfer.
Note: Examples of coupling include capacitive (electrostatic) coupling, inductive (magnetic) coupling, conducted (resistive or hard-wire) coupling, and fiber-optic coupling.
Source: from Federal Standard 1037C and from MIL-STD-188
Coupling is also a television comedy series from the UK with an American adaptation.