Virtual memory is a term used to describe the use of hard disk space as an extension of physical memory. There are different synonyms for this term, depending on the context and the particular technical jargon found in various disciplines. In computer science, some alternatives to virtual memory are paging or swapping. In operating systems, this term can also be called a page file or swap file. The concept of virtual memory is related to storage technologies such as flash memory, which can be referred to as solid-state disk (SSD) or non-volatile storage. Finally, terms like memory swapping or dynamic memory allocation are often used interchangeably with virtual memory.