An internally displaced person (IDP) is someone who has been forced to leave their homes due to conflict, natural disasters, or other reasons, but they have not crossed international borders. They remain within their own country. On the other hand, a refugee is someone who has been forced to flee their country due to persecution, war, or violence and seeks refuge in another country. In this case, both IDPs and refugees are individuals who have been displaced from their homes, but the key difference is that IDPs have not left their countries while refugees have crossed international borders.