heir

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A person who inherits or is entitled by law or by the terms of a will to inherit the estate of another.
• noun A person who succeeds or is in line to succeed to a hereditary rank, title, or office.
• noun One who receives or is expected to receive a heritage, as of ideas, from a predecessor.

from The Century Dictionary.

• noun One who inherits, or has a right of inheritance in, the property of another; one who receives, or is entitled to receive, possession of property or a vested right on the death of its owner, either as his natural or as his legal successor.
• noun Technically, in law, the person upon whom the law casts an estate in real property immediately on the death of the ancestor, as distinguished from one who takes by will as a legatee or devisee, and from one who succeeds by law to personal property as next of kin. The same person who is heir when considered with reference to realty is often also next of kin when considered with reference to personalty: and where a testator's will disposes of part only of his realty, the same person who takes under the will as devisee may also take an undisposed-of part as heir. In this sense the word as used at common law does not include a widow on whom the law casts an estate in dower, or a husband on whom the law casts an estate by the courtesy, for these are considered new estates, arising out of marriage and its incidents, and carved out of the fee, not as a continuation or devolution of the fee itself. If there be dower or courtesy, the heir is that person who takes immediate title to the fee, subject to such life-estate. In legal phrase heir and heir at law are commonly used in England in the singular, because the general rule of descent there has given the entire estate to the eldest male. The singular is also not uncommonly used in the United States to designate whoever may be entitled, whether one or more, because of English usage, and because appropriate in all cases where there is but one standing in the nearest degree to the deceased.
• noun In a broader sense, in those jurisdictions where the distinction between realty and personalty is disregarded, the person entitled by law to succeed one dying in respect of either kind of property, as distinguished from those taking by will. In jurisdictions where the distinction is preserved, a testamentary gift of personalty, expressed to be to one's heirs, is commonly understood to intend his next of kin.
• noun In another extended sense, one in a series of heirs; any successive inheritor, including not only him who takes immediately upon the death of the ancestor, but also those who have inherited through several successive descents, In the most general sense, the person upon whom property of any kind devolves on the death of another, either by law or by will. Thus, the children of a person deceased are popularly spoken of as his heirs, irrespective of the nature of the property or the mode in which it passed. In much this sense heres was used in the Roman law.
• noun One who inherits anything; one who receives any endowment by inheritance or transmission.
• noun A child regarded with reference to anything due to his parentage; an offspring in general.
• noun children and lawful descendants;
• noun parents and lawful ascendants;
• noun collateral kindred.
• To inherit; succeed to.

from the GNU version of the Collaborative International Dictionary of English.

• noun 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.
• noun One who receives any endowment from an ancestor or relation.
• noun (Law.) See under Apparent.
• noun one who, after his ancector's death, has a right to inherit all his intestate estate.
• noun 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.
• transitive verb rare To inherit; to succeed to.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Someone who inherits, or is designated to inherit, the property of another (Wikipedia).
• noun One who inherits, or has been designated to inherit, a hereditary title or office.
• noun A successor in a role, representing continuity with the predecessor.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a person who inherits some title or office
• noun a person who is entitled by law or by the terms of a will to inherit the estate of another