Objects or processes (as used in the informal definition, extend software to the rest of the world to
We need the generalisation of those XP-derived terms to built a terminology for ExtremeOpenBusiness, where we speak of business processes and business objects. -- FridemarPache
(Note to people who enjoy inspiration from mathematical category theory: processes are morphisms between objects, called sources and targets)
It may be described informally, or may be described in a more formal language such as UML (, or category theory).
Use Cases Tutorial - http://www.parlezuml.com/tutorials/usecase/intro.htm