Heir:—

Heir means any person, male or female, who is entitled to succeed to the property of an intestate under this Act, [Section 3(f), Hindu Succession Act, 1956.
The word “heirs” cannot normally be limited to “issues” only. It must mean all persons who are entitled to the property of another under the law of inheritance, N. Krishnammal v. R. Ekambaram, (1979) 3 SCC 273. 3. A person who succeeds by descent to an estate of inheritance. It is nomen collectivum and extends to all heirs; and under heirs, the heirs of heirs are comprehended in infinitum.

Heirdom — Succession by inheritance.

Heiress— A female heir. Where there are several, they are called co-heiresses.

Heirloom — Personal chattels, such as charters, deeds and evidences of title, which go to the heir, together with the inheritance. The term ‘heirlooms’ is often applied in practice to the case where certain chattels — for example, pictures, plate or furniture — are directed by will or settlement to follow the limitations thereby made of some family mansion or estate. But the word is not then employed in its strict and proper sense, nor is the disposition itself beyond a certain point effectual; for the articles will, in such case, belong absolutely to the first person who, under the limitations, would take a vested estate of inheritance in them supposing they had been real estate; and if he die intestate, will pass to his personal representatives and not to his heir.

Heir, Heir at law and Heir testamentary :— The meaning of these words in Black’s Law Dictionary, relied upon by Supreme Court viz.: Heirs — At common law, the person appointed by law to succeed to the estate in case of intestacy. One who inherits property, whether real or personal. A person who succeeds, by the rules of law, to an estate in lands, tenements or hereditaments, upon the death of his ancestor, by descent and right of relationship. One who would receive his estate under statute of descent and distribution. Faulkner’s Guardian v. Faulkner, 237 Ky 147: 35 SW 2d 6, 7. Moreover, the term is frequently used in a popular sense to designate a successor to property either by will or by law. Heir at law — At common law, he who, after his ancestor dies intestate, has a right to all lands, tenements and hereditaments which belonged to him or of which he was seised. The same as ‘heir general’. A deceased person’s ‘heirs at law’ are those who succeed to his estate of inheritance under statutes or descent and distribution, in absence of testamentary disposition and not necessarily his heirs at common law, who are persons succeeding to deceased’s realty in case of his intestacy. Heir testamentary — In the civil law, one who is named and appointed heir in the testament of the decedent. This name distinguishes him from a legal heir (one upon whom the law casts the succession) and from a conventional heir (one who takes it by virtue of a previous contract or settlement).”, Vasant Pratap Pandit v. Anant Trimbak Sabnis, (1984) 3 SCC 481,  487 (para 13).