Sultan and king are two designation, which were commonly used before 19th century to represent the ruler of a country. They are still rarely used in some countries but now they are used for honor and respect. With the passage of time, to some extent real meaning of both term are not used now. Some leaders and rulers still used these words just as a formality.
Sultan is an Arabic word, which represents the strength and power of an individual who ruled on lands refereed as a sultanate. Most of the leaders and powerful personality of Arabian countries still used the word sultan for them though there is no area ruled by them. Now it is used just as a noble word. The word sultan is religious word in the sense that it is used in the Quran, which denotes to the ruler of the country. It was widely used in past in Africa to represents the kingdom of a ruler in a country. Later on it became popular in Asian kingdom history as well.
King or monarchy is the word, which represents the government of one or two individuals. It is a kind of autocratic government in which a single or two persons controls the whole authority of the state. Concept of king was most popular in European countries and later on was also adopted by Asian rulers. Up to 19th century it was most common form of government but now it is no longer prevalent. There are just few countries in the world in which word king is still used for the head of state. Ruler of Saudi Arabia and some states of United Arab Emirates still used the word king for them.
- Sultan is a pure Arabic word which was commonly used to represent the ruler of Muslims countries while King is a general word which was equally used in European, Arab and Asian countries.
- Sultan is now a totally no practical term. No modern state is known as a sultanate of a specific sultan or ruler. However the word king and kingdom is still used in some countries like Kingdom of Saudi Arabia ruled by King Abdullah.
- Sultan ruled a limited land while king was the ruler of a huge kingdom.
- Sultan was also used as the name of a general person and to give honor to person either he was a ruler or not. While king was used to represent the head of the state.