permission vs allowance

permission and allowance both are nouns.

Word	Noun	Adjective	Verb	Adverb
permission	Yes	No	No	No
allowance	Yes	No	Yes	No

As nouns, allowance is a hyponym of permission; that is, allowance is a word with a more specific, narrower meaning than permission:

Other hyponyms of permission include clearance, conge, congee, dispensation, toleration.

permission (noun)	allowance (noun)
the act of giving a formal (usually written) authorization	the act of allowing
approval to do something	a permissible difference; allowing some freedom to move within limits
	an amount allowed or granted (as during a given period)
	an amount added or deducted on the basis of qualifying circumstances
	a sum granted as reimbursement for expenses
	a reserve fund created by a charge against profits in order to provide for changes in the value of a company's assets

permission (verb)	allowance (verb)
	put on a fixed allowance, as of food