Creating Your First Multidimensional Cube - Getting Started with SQL Server 2012 Cube Development - page 61

More information about the attribute relationships can be found at ht-
tp://msdn.microsoft.com/en-us/library/ms174878.aspx .
A dimension can also contain something called hierarchies. A hierarchy is a group-
ing of attributes organized in a specific order. The order of the attributes defines the
different levels that you will find in the hierarchy, on the top you will find the All level
and then the attributes in the levels defined by the order of them, and the attribute
relationships. The following figure shows the Date dimension and the hierarchy of
the attributes: