Universes can also be defined as a Meta-Data layer between the user and the database. All of the links between tables are defined in the universe, fields (called Dimensions) are given plain English names, and common calculations and formulas are set up with plain English names. This way your users don't need to know much, if anything, about the underlying database in order to build reports.
-Dell
A computer only does what you actually told it to do - not what you thought you told it to do.