archive

1. <file format> A single file containing one or (usually) more separate files plus information to allow them to be extracted (separated) by a suitable program.

Archives are usually created for software distribution or backup. tar is a common format for Unix archives, and arc or PKZIP for MS-DOS and Microsoft Windows.

2. <operating system> To transfer files to slower, cheaper media (usually magnetic tape) to free the hard disk space they occupied. This is now normally done for long-term storage but in the 1960s, when disk was much more expensive, files were often shuffled regularly between disk and tape.