In the context of the English peerage and the law of primogeniture, an Heir Apparent possesses an indefeasible right to succession. Unlike an heir presumptive, whose status may be displaced by the birth of a more senior claimant—such as a son born to the current titleholder—the Heir Apparent's position is fixed by law and lineage. This distinction evolved alongside the transition from elective or purely feudal tenures to hereditary peerages created by writ or letters patent, ensuring stability in the devolution of dignity and landed power.
From a heraldic perspective, the Heir Apparent of a peer is entitled to use their father's secondary titles as 'courtesy titles' and may differencing their family coat of arms with a label of three points. This cadency mark serves as a public declaration of their status as the immediate successor. In the royal sphere, the Sovereign’s eldest son is born Duke of Cornwall and is typically created Prince of Wales, though the latter remains a grant at the monarch's pleasure rather than an automatic inheritance.