You can create a metadata domain to have a model available to end-users and applications that allows them to enhance their data. By using formatting, security metadata, and custom metadata, you can produce a more efficient model, with a consistent and clearer view of the data.
A property has an identifier (a key into a map actually) and a value. This collection of properties is the map of attributes that you want to apply to a particular business object, such as a business column or business table. A concept is the metadata you define for your business objects. Each business object (physical table, business table, columns, and so on) has its own concept whose properties override all other inherited or parent concepts.
Concepts can also be defined independent of any business object and can be structured in an inheritance hierarchy for better organization and management of your metadata. These independent concepts can then be applied to one or more business objects as a parent concept.