Heir is a person who is legally entitled to inherit some or all of the estate of another person who has died intestate (without a will).
The term "heir" is commonly used in the following contexts:
1. Heir apparent - an heir whose right to inherit is indefeasible
2. Heir presumptive - an heir whose right may be defeated by the birth of a more eligible heir
3. Heir at law - a person who inherits under the laws of intestacy
4. Heir to the throne - the next in line to inherit a royal title