fideicommissum
A benefit bequeathed to a beneficiary who inherits the benefit, subject to the obligation of bequeathing it to another.
I bequeath my farm to my brother John on condition that he bequeath it to his son Peter. The farm is entailed or burdened by a fideicommissum.
Where it comes from
Latin fidei (“trust”) (genitive) + commissum, from committō (“give, entrust”), from con- + mittō (“to send”).
Adapted from the Wiktionary entry fideicommissum (CC BY-SA 4.0).