Metadata Catalog
From GridPP Wiki
Metadata catalogs are like grid File Catalogs, but specialise in holding auxilliary data specific to a VO (or LHC experiment).
In the context of LCG, experiments will have their own metadata catalogs, which will contain the link to File Catalogs through the Logical File Name.
More information about metadata and metadata catalogs is avaliable in the GridPP Metadata Wiki.