A name for an imaginary place of great beauty, luxury and peace — a kind of earthly paradise that is always slightly out of reach. Say it "ZAN-a-doo"; the X at the front sounds like a z. It comes from Coleridge's poem Kubla Khan, which opens with a great pleasure-palace built at Xanadu, and the poem's dreamlike feeling is what the word carries with it: not just a lovely place, but a place too lovely to be quite real, or one that vanishes when you wake. English speakers use it in two ways. Sometimes it is straightforward praise, a rich or beautiful place described as a Xanadu. More often there is a hint of irony or sadness — someone's private Xanadu is a paradise built for one person, a little grand and a little foolish, as with the enormous house called Xanadu in the film Citizen Kane. It is a literary word, not everyday speech; you meet it in newspapers, travel writing, and film and book titles rather than in conversation. Worth knowing for students here: the real place existed. Xanadu was Kublai Khan's summer capital in Inner Mongolia, and Marco Polo wrote about it, so the fairy-tale name is a real Chinese city seen through several layers of retelling.