1. formally make or acknowledge a transfer of something.
▪ transfer (something) to someone else:"a lord might attorn his vassals service to some other"
Word OriginMiddle English (in the senses ‘turn, change, transform’): from Old French atorner ‘appoint, assign’, from a- (from Latin ad ‘to, at’) + torner ‘to turn’. The spelling with o rather than u or ou, as might have been expected in English, is due to the late Anglo-Norman French form attorner, adopted in legal use.