late 14c., "something granted; authoritative bestowal of a privilege, etc.," from Anglo-French graunt, Old French graant, collateral variant of creant "promise, assurance, vow; agreement, pact; will, wish, pleasure," from creanter "be pleasing; assure, promise, guarantee; confirm, authorize" (see grant (v.)). Earlier in English in now-obsolete sense of "allowance, permission" (c. 1200). Especially "money formally granted by an authority" from c. 1800. In American English, especially of land, from c. 1700.
in early use also graunt, early 13c., "to allow, permit (something); consent to (a prayer, request, etc.)," from Old French graanter, variant of creanter "assure, promise, guarantee, swear; confirm, authorize, approve (of)," from Latin credentem (nominative credens), present participle of credere "to believe, to trust" (see credo). From c. 1300 as "transfer possession of in any formal way." Meaning "admit to be true, acknowledge" in English is from c. 1300; hence to take (something) for granted "regard as not requiring proof" (1610s). The irregular change of -c- to -g- in Old French is perhaps from influence of garantir. Related: Granted; granting.