(1) In computer science, loose coupling (or loosely coupled) is a type of coupling that describes how multiple computer systems, even those using incompatible technologies, can be joined together for transactions, regardless of hardware, software and other functional components. Loosely coupled systems describe those that work on an exchange relationship where little input is needed from each of the additional systems. In a loosely coupled system hardware and software may interact but they are not dependant on each other to work. Computers in a network are considered loose-coupled systems as a client machine may request data from the server, but the two systems also work independently of each other.
(2) In software terminology, loosely coupled refers to software where routines, modules, functions, and similar components are executed only as needed, and do not run at the launch of the software application and while it is being used. Web services are a type of software application that uses loose coupling.