Prince of Wales is a title traditionally given to the male heir apparent to the English and, later, British thrones. The title originated with the Welsh rulers of Gwynedd who, from the late 12th century, used it to assert their supremacy over the other Welsh rulers. However, to mark the finalisation of his conquest of Wales, in 1301, Edward I of England invested his son Edward of Caernarfon with the title, thereby beginning the tradition of giving the title to the heir apparent when he was the monarch's son or grandson. The title was later claimed by the leader of a Welsh rebellion, Owain Glyndŵr, from 1400 until 1415.

An heir apparent or simply heir is a person who is first in an order of succession and cannot be displaced from inheriting by the birth of another person. A person who is first in the current order of succession but could be displaced by the birth of a more eligible heir is known as heir presumptive.