Back in the day, when we had more monarchies, a king was the person that ruled the entire land. It was a male ruler, a ruler of an independent nation/state, and you could inherit the throne, so your male hair would become king after you. In some instances it was passed down from father to son. To sum up, a king is a male sovereign or monarch; the position is usually hereditary, and the king is the chief authority over a country and people.