Heir , (Lat. hoeres), in law, one entitled by descent and right of blood to lands, tenements, or other hereditaments. There are two ways in law in which the title to real estate may pass, by purchase and by descent. It is said to be by purchase when it is transferred by the owner by any species of gift, grant, or conveyance, to take effect either in his lifetime or by way of testamentary disposition ; and it is by descent when, by reason of his dying intestate, it passes to such relative or relatives as by law are designated to succeed to his real property in that contingency. The word heir is sometimes used in a popular sense as signifying any one to whom property of any description is to pass on the death of its owner, whether by conveyance or by operation of law; and when it is thus employed in wills or other instruments, the law seeks to give effect to the instrument according to the real intent of the party, though the word is misapplied. In a legal sense no one is heir to personal property, and though the law in this country usually gives the real and personal property of an intestate to the same persons, the latter goes first to the administrator, through whom it is distributed after the debts are paid.

In the Roman civil law, the word hoeres, which we translate heir, meant any one called to the succession, by blood, devise, or bequest, and whether the property to which he succeeded was fixed or movable. - An heir apparent is one who must be the heir if he survive the owner, as the eldest son in England, or all the children in the United States. But the phrase "heir apparent" is not strictly applicable here. In England, the birth of a younger son cannot affect the rights of inheritance of the eldest son, for they are fixed, and he alone can be heir by descent. But in this country the younger son has an equal right with an elder son ; and therefore the exclusive right of inheritance can never be fixed in any children living. - An heir presumptive is one who, if things do not change, will be the heir at the death of the owner, as the elder son of a deceased brother in England, or all the children of a brother in the United States, where the owner has no children ; for they will be heirs if he dies without issue.

As an heir presumptive may lose his heirship by a change of circumstances, he does not become an heir apparent so long as this change is legally probable, although physically or naturally impossible.