Pupose of ampersand (&) character in MDX

In MDX Query, A member can be referenced by either its member name or by its member key


The ampersand (&) character is used in MDX to differentiate a member key from a member name, as shown in the following example:


Reference the member by its member Key:
[Time].[2nd half].&[Q4]


Reference the member by its member name:
[Time].[2nd half].[4th quarter]