Attornment

Ian McEwan's little-read prequel to Atonement, set in WWI, with a plot put into motion by someone writing curse words on a postcard that got ripped in half.
Actually, it's a fancy word related to the transfer of rights when a property changes ownership. You can tell it's fancy because it originally comes from French ("tourner" or "to turn") and gets handed down to us through British law.
Example:
You are leasing an apartment. Your landlord sells the apartment building to someone else. Attornment means that you agree to continue being a tenant under the same terms under the new landlord. The rights related to that lease get transferred along with the sale of the building.