a system whereby addressable memory is extended beyond main storage through the use of secondary storage managed by system software in such a way that programs can treat all of the designated storage as addressable main storage.
British Dictionary definitions for virtual storage
virtual storage
virtual memory
noun
a computer system in which the size of the memory is effectively increased by automatically transferring sections of a program from a large capacity backing store, such as a disk, into the smaller core memory as they are required
