Definition - What does Swap File mean?
A swap file is a Microsoft Windows hard disk drive file (HDD) that provides virtual memory to its OS and programs and supplements the system's existing solid state physical memory.
A swap file is also known as a swap space, page file, pagefile or paging file.
Techopedia explains Swap File
Introduced to supplement physical PC memory limitations, swap files are still used in operating systems like Windows 7 and Windows Server 2008, as virtual memory is a cheaper alternative to magnetic media. A typical swap file is equal to or larger than the system's total installed physical memory. The exact size is based on the OS and amount of physical memory, as well as applicable personal and/or corporate policies and preferences.
Although swap files provide additional system memory, the data stored in swap files is typically less active or idle because HDD transfer and access speeds are much lower than solid state memory.