your Look up your at Dictionary.com
Old English eower, genitive of ge "ye" (see ye), from Proto-Germanic base of you. Cf. Old Saxon iuwar, Old Frisian iuwer, Old Norse yðvarr, Old High German iuwer, German euer, Gothic izwar "your."

Used in titles of honor by mid-14c. Absolutive form yours is attested from c.1300. For dialectal yourn, see her. Yours truly "myself" is from 1833, from the common subscription of letters.