attorn vi[Anglo-French aturner to transfer (allegiance of a tenant to another lord), from Old French atorner to turn (to), arrange, from a - to + torner to turn]
: to agree to be the tenant of a new landlord or owner of the same property
Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.