Perhaps just a business oriented metadata layer... This « thing » made the fortune of Business Objects creating an intermediate layer between business people talking about invoices, customers, margin... and IT people more focusing on tables, indexes and SQL orders.
All open source BI tools have been made by IT people and were keeping a very technical way of seeing queries.
Pentaho just announced the release 1.6 including for the first time this famous metadata layer. I didn't check it yet but it could be a signal for more business oriented BI users to imagine a migration to BI open source solutions. Anyway just for an intellectual comparison you should look at it.