An estate in fee entailed, or limited in descent to a particular class of issue.

The rule by which the descent is fixed.

To settle or fix inalienably on a person or thing, or on a person and his descendants or a certain line of descendants; -- said especially of an estate; to bestow as an heritage.

Entail was a legal term meaning that a landed estate was tied up in such a way that the person inheriting it would have only its income and could not sell or mortgage it. Along with primogeniture, it was the legal basis of the British aristocracyâ€(tm)s ability to transmit their great estates intact down through the centuries.

We say that α1 ... αn entail β if and only if it is logically impossible for α1 ... αn to be true and β to be false at the same time. In SL, this means that there is no assignment of truth-values under which cally impossible for α1 ... αn are all true and β is false.

have as a logical consequence; "The water shortage means that we have to stop taking long showers"

From RDF Semantics ( 2004-02-10) (v.), (n.). A semantic relationship between expressions which holds whenever the truth of the first guarantees the truth of the second. Equivalently, whenever it is logically impossible for the first expression to be true and the second one false. Equivalently, when any interpretation which satisfies the first also satisfies the second. (Also used between a set of expressions and an expression.)