The term 'AGA' can be solved by the four-letter word 'KHAN'. The term 'KHAN' is a title of nobility used in many parts of the world, most notably in Central and South Asia. It is derived from the Turkic and Mongolian word 'KHAN', meaning 'LEADER' or 'RULER'. In some countries, it is also used as a surname. Historically, the title was used by rulers of the Mongol Empire and other Turkic dynasties, and is still used today in some Muslim countries.