The Collaborative International Dictionary of English v.0.48:
Changan \Changan\ n. the capital of the ancient Chinese empire. Syn: Sian, Singan, Xian. [WordNet 1.5]WordNet (r) 3.0 (2006):
Changan n 1: a city of central China; capital of ancient Chinese empire 221-206 BC [syn: Xian, Sian, Singan, Changan, Hsian]