Merriam-Webster's Collegiate® Dictionary, 11th Edition
ENTAIL
I. transitive verb see: tail
Date: 14th century
to restrict (property) by limiting the inheritance to the owner's lineal descendants or to a particular class thereof,
2. to confer, assign, or transmit as if by entail ; fasten , to fix (a person) permanently in some condition or status , to impose, involve, or imply as a necessary accompaniment or result , entailer noun entailment noun
II. noun
Date: 14th century
1. an entailing especially of lands, an entailed estate, something transmitted as if by entail