WordNet (r) 3.0 (2006):

unzip
    v 1: open the zipper of; "unzip the bag" [ant: zip, zip up,
         zipper]

The Free On-line Dictionary of Computing (30 December 2018):

unzip

   1.  To extract files from an archive
   created with PKWare's PKZIP archiver.

   2.  A program to list, test, or extract
   files from a ZIP archive, commonly found on MS-DOS
   systems.  zip, creates ZIP archives; both programs are
   compatible with archives created by PKWARE, Inc.'s PKZIP
   and PKUNZIP for MS-DOS.

   (1995-03-06)