Ku·blai Khan (ko?o?bl? kän?) also Ku·bla Khan (-bl?) 1215-1294. Mongol emperor (1260-1294) and founder of the Mongol dynasty in China. A grandson of Genghis Khan, he conquered the Song dynasty (1279) and established a great capital, now Beijing, where he received Marco Polo (1275-1292).American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.