Definition of Entail
v. To settle or limit the succession to real property; to create an estate tail.
n. A fee abridged or limited to the issue, or certain classes of issue, instead of descending to all the heirs.
Break or bar an entail. To free an estate from the limitations imposed by an entail and permit its free disposition, anciently by means of a fine or common recovery, but later by deed in which the tenant and next heir join.
Quasi entail. An estate pur autre vie may be granted, not only to a man and his heirs, but to a man and the heirs of his body, which is termed a “quasi entail;” the interest so granted not being properly an estatetail (for the statute De Donis applies only where the subject of the entail is an estate of inheritance), but yet so far in the nature of an estate-tail that it will go to the heir of the body as special occupant during the life of the cestui que vie, in the same manner as an estate of inheritance would descend, if limited to the grantee and the heirs of his body.
That's the definition of Entail in Black's Law Dictionary 6th Edition. Courtesy of Cekhukum.com.
