Heir presumptive

An heir presumptive or heiress presumptive is the person entitled to inherit a throne, peerage, or other hereditary honour, but whose position can be displaced by the birth of an heir apparent, male or female, or of a new heir presumptive with a better claim to the position in question. The position is however subject to law and/or conventions that may alter who is entitled to be heir presumptive.

Depending on the rules of the monarchy the heir presumptive might be the daughter of a monarch (if males take priority over females and the monarch has no sons), or the senior member of a collateral line (if the monarch is childless); the birth of a legitimate child to the monarch will displace the former heir presumptive by a new heir apparent or heir presumptive. It is not assumed that the monarch and his or her consort are incapable of having further children; the day before Queen Elizabeth II of Great Britain ascended the throne her father was gravely ill and her mother was in her early 50s, but Elizabeth was still considered the heir presumptive rather than the heir apparent.