A data store is a repository for persistently storing and managing collections of data which include not just repositories like databases, but also simpler store types such as simple files, emails, etc.[1]
A database is a collection of data that is managed by a database management system (DBMS), though the term can sometime more generally refer to any collection of data that is stored and accessed electronically. A file is a series of bytes that is managed by a file system. Thus, any database or file is a series of bytes that, once stored, is called a data store.
MATLAB[2] and Cloud Storage systems like VMware,[3] Firefox OS[4] use datastore as a term for abstracting collections of data inside their respective applications.
A place where data is stored; data at rest. A generic term that includes databases and flat files.