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