The present participle or gerund form of 'authorize'; the act of giving official permission or approval (British spelling).
From 'authorize' (from Old French/Latin 'auctorizare') plus '-ing' (Old English suffix forming gerunds and present participles). The '-ise' spelling follows British conventions.
The difference between 'authorizing' something and 'permitting' it is subtle but legally important—authorizing often means officially endorsing and taking responsibility, while permitting can be more passive.
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