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]

Moby Thesaurus II by Grady Ward, 1.0:

78 Moby Thesaurus words for "permission":
   John Hancock, OK, acceptance, accord, acquiescence, affirmance,
   affirmation, affirmative, affirmative voice, agreement, allowance,
   approbation, approval, assent, authentication, authorization, aye,
   blessing, certification, charter, compliance, confirmation,
   connivance, consent, countenance, countersignature,
   diplomatic immunity, discharge, eagerness, endorsement,
   enfranchisement, exception, exemption, franchise, go-ahead,
   green light, immunity, imprimatur, indulgence, laxity, leave,
   legislative immunity, lenience, leniency, liberty, license, nod,
   notarization, okay, patent, permit, privilege, promptitude,
   promptness, ratification, readiness, release, rubber stamp,
   sanction, seal, sigil, signature, signet, stamp, stamp of approval,
   submission, subscription, sufferance, the nod, tolerance,
   ungrudgingness, unloathness, unreluctance, validation, visa, vise,
   warrant, willingness



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

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)


Bouvier's Law Dictionary, Revised 6th Ed (1856):

PERMISSION. A license to do a thing; an authority to do an act which without
such authority would have been unlawful. A permission differs from a law, it
is a cheek upon the operations of the law.
     2. Permissions are express or implied. 1. Express permissions derogate
from something which before was forbidden, and may operate in favor of one
or more persons, or for the performance of one or more acts, or for a longer
or shorter time. 2. Implied, are those, which arise from the fact that the
law has not forbidden the act to be done. 3. But although permissions do not
operate as laws, in respect of those persons in whose favor they are
granted; yet they are laws as to others. See License.