de‧com‧press /ˌdiːkəmˈpres/ verb [transitive]

1. to reduce the pressure of air on something

2. technical to change the information in a computer document back into a form that can be easily read or used, when the information was stored on the computer in a special form that used less space in the computer’s memory:
Most Macintosh computers can decompress files automatically.
—decompression /-ˈpreʃən/ noun [uncountable]

[TahlilGaran] Dictionary of Contemporary English ▲