The Collaborative International Dictionary of English v.0.48:

Permission \Per*mis"sion\ (p[~e]r*m[i^]sh"[u^]n), n. [L.
   permissio: cf. F. permission. See Permit.]
   The act of permitting or allowing; formal consent;
   authorization; leave; license or liberty granted.
   [1913 Webster]

         High permission of all-ruling Heaven.    --Milton.
   [1913 Webster]

         You have given me your permission for this address.
                                                  --Dryden.
   [1913 Webster]

   Syn: Leave; liberty; license.

   Usage: Leave, Permission. Leave implies that the
          recipient may decide whether to use the license
          granted or not. Permission is the absence on the part
          of another of anything preventive, and in general, at
          least by implication, signifies approval.
          [1913 Webster]

WordNet (r) 3.0 (2006):

permission
    n 1: approval to do something; "he asked permission to leave"
    2: the act of giving a formal (usually written) authorization
       [syn: license, permission, permit]

The Free On-line Dictionary of Computing (19 January 2023):

permission
access permission

    (Or "file mode") The ability to access (read,
   write, execute, traverse, etc.) a file or directory.
   Depending on the operating system, each file may have
   different permissions for different kinds of access and
   different users or groups of users.

   chmod ("change mode") is the UNIX command to change
   permissions.

   (2000-12-07)