Create a class model that describes domain concepts
Create a class model that describes domain concepts, their interrelationships, collaborations and constraints, but contains no further information on any specific system or on how any system is to be used.
A model of the domain has certain uses and certain useful properties. It may be used as the basis of multiple system development projects within the domain of business, it may be used as the basis of business modeling, and it may be used as the basis of communication between businesses within and across domains. One useful property is that domain models tend to change by expanding rather than by altering of existing parts of the model. This latter can happen, but is usually indicative of mistakes or short cuts having been made. Some approaches to domain modeling include assigning responsibilities to the classes representing the domain concepts, see ResponsibilitiesInTheRightPlace.
1. Domain Modelling essay by Paul Oldfield (pdf file)
2. Agile Requirements Challenge #8. Stakeholders are Unable to See Beyond the Current Situation