What is another word for database?

There isn't really a single perfect synonym for "database", but here are some alternatives depending on the context:

Formal:

* Data repository

* Data store

* Data collection

* Information system

* Data management system

Informal:

* Data pool

* Data vault

* Data center (though this refers to the physical location)

* Information archive

More specific:

* Relational database (if it's a relational database)

* NoSQL database (if it's a NoSQL database)

* Graph database (if it's a graph database)

The best word to use will depend on the specific situation and your desired level of formality.