heir presumptive

Webster's Dictionary (GCIDE)

1.One who inherits, or is entitled to succeed to the possession of, any property after the death of its owner; one on whom the law bestows the title or property of another at the death of the latter. [1913 Webster]

I am my father's heir and only son.— Shak.[1913 Webster]

2.One who receives any endowment from an ancestor or relation; as, the heir of one's reputation or virtues. [1913 Webster]

And I his heir in misery alone.— Pope.[1913 Webster]

Heir apparent. (Law.) See under Apparent.

Heir at law, one who, after his ancector's death, has a right to inherit all his intestate estate. --Wharton (Law Dict.).

Heir presumptive, one who, if the ancestor should die immediately, would be his heir, but whose right to the inheritance may be defeated by the birth of a nearer relative, or by some other contingency. [1913 Webster]