: a man of authority who bears a title of respect: such as
a
: a military or civil officer in the Ottoman Empire
a vast body of dragoons … under … their great aga Jonathan Swift
b
: a Turkish chief
the khans … and agas … are probably the oldest landed aristocracy of the world Harold Lamb
c
: a religious leader
the Aga Khan … claims descent from Fatima H. G. Rawlinson
Word History
Etymology
borrowed from Ottoman Turkish ağa "lord, master, respected man (in titles)," going back to Medieval Turkic, literally, "older brother," borrowed from Mongolian (Uigur-script) aqa, (Arabic-script) āqā "older brother"