In storage terminology, the term consolidation is used mainly to refer to the concept of centralized storage where resources are shared among multiple applications and users.
Traditionally, organizations have deployed servers with direct-attached storage (DAS) as file servers. However, many organizations are facilitating server consolidation by deploying network-attached storage (NAS). NAS provides a single purpose device that can provide CIFS and NFS connected storage that can scale from gigabyte to petabytes.
See also The Benefits of Tiered Storage in Webopedia’s “Did You Know…” section.