From late 14c. as "freedom; not being in servitude; social status of a freeman;" early 15c. as "citizenship, membership in a community or town; membership in a craft or guild." The "special right" sense narrowed 18c. to "particular legal privilege," then "right to vote" (1790). From mid-15c. as "right to buy or sell," also "right to exclude others from buying or selling, a monopoly;" meaning "authorization by a company to sell its products or services" is from 1959.
early 15c., "a citizen, a dweller, an inhabitant," especially "legally established inhabitant of a city or borough, a citizen as distinguished from a non-resident native or a foreigner," from Anglo-French deinzein, denzein, (Old French deinzein) "one within" (the privileges of a city franchise; opposed to forein "one without"), from deinz "within, inside," from Late Latin deintus, from de- "from" + intus "within" (see ento-).
Historically, an alien admitted to certain rights of citizenship in a country; a naturalized citizen (but ineligible to public office). Formerly also an adjective, "within the city franchise, having certain rights and privileges of citizenship" (late 15c.). Compare foreign.
mid-15c. (late 13c. in Anglo-French), "royal writ to determine by what warrant a person holds an office or franchise," a Medieval Latin legal phrase, literally "by what warrant," from quo "from, with, or by whom or what?," ablative of the interrogative pronoun quis "who?" (from PIE root *kwo-, stem of relative and interrogative pronouns). Also see warrant (n.).