Definition - What does Heir Apparent mean?
An heir apparent is a person who is presumed to be the heir to an estate, or to a position due to relation to the person of interest or to other forms of credibility. Heirs apparent are usually, but not necessarily always the people who inherit the estate or position of a deceased person.
Justipedia explains Heir Apparent
A simple example of an heir apparent would be the first born son of a king. In this case, the son, or the prince, would be expected to inherit the throne upon the death of his father. However, it could be possible for the son could be disinherited, and thus not inherit the throne, if the king had reason to do so. The throne would thus pass onto another relative. For example, the king could pass the throne onto a daughter, or a brother instead. If the heir apparent in question for the example was a second born son and there is a first born son, the second born son is still an heir apparent, but he would not necessarily inherit the crown.