The term 'KHAN (Islamic leader)' can be summarized by the crossword solutions of 'AGA' which is a three letter word. AGA is a title of honor used in many Islamic countries, especially Turkey, to refer to a nobleman or a military commander. It is derived from the Mongolian title 'KHAN', which was used by Genghis KHAN and his successors to refer to their rulers. The title was later adopted by the Ottoman Empire and other Muslim states in the Middle East and Central Asia. In modern times, the title is still used in some Muslim countries as a sign of respect for a leader or a high-ranking official.