Inolder literature, you’ll often see Genghis Khan and his Mongols called “Tartars” or “Tatars.” We no longer label the Mongols as Tatars. Today, Tartar refers to Turkic-speaking people of Eastern Europe, Russia, and Central Asia, such as the Crimean Tartars. They aren’t related to the Genghis and his descendants.
Though using Tartar for Mongols has fallen out of favor in academic circles, it persists in popular culture. Travel writer and journalist Justin Marozzi addresses Timur as a “Tartar” in his acclaimed work Tamerlane: Sword of Islam, Conqueror of the World.