Enterprise storage refers to a centralized data depository that is designed for the needs of a large organization. Enterprise storage performs the same functions as smaller scale data storage solutions, but is more reliable and fault tolerant. Enterprise storage can also be scaled up to serve a large user base and heavy workloads without significantly slowing down the system.
Techopedia explains Enterprise Storage
Although enterprise storage does provide huge amounts of storage, the selling point for most organizations is the high availability of data and the system's overall reliability. Enterprise storage is used for critical systems and data that would result in a business halt if it were inaccessible or destroyed. Like many enterprise-class solutions, there is no standard to which a storage system can be compared in order to classify it as enterprise.