A model is a pattern, plan, representation (especially in miniature), or description designed to show the main object or workings of an object, system, or concept.
The reason is that there are a number of clear benefits that models provide a development organization. They are
ￃﾠ Enhanced communication
ￃﾠ Better planning
ￃﾠ Reduced Risk, and
ￃﾠ Reduced costs
Modeling can help us to check our understanding.