Use attribute dimensions to classify members of another, associated dimension. For example, in the Sample Basic database, the Pkg Type attribute dimension contains a member for each type of packaging, such as bottle or can, that applies to members of the Product dimension.
To tag an attribute dimension:
Open the outline in edit mode.
The Outline tab is displayed.
Right-click a dimension and select Edit member properties.
In the Member Properties dialog box, select the Information tab.
Under the Member Information node, in the Dimension type drop-down list, select Attribute.
Click OK.
“Working with Attributes” in the Oracle Essbase Database Administrator's Guide