Singan vs Sian

Singan and Sian both are nouns.

Word	Noun	Adjective	Verb	Adverb
Singan	Yes	No	No	No
Sian	Yes	No	No	No

As nouns, Singan and Sian are synonyms defined as:

Singan and Sian: a city of central China; capital of ancient Chinese empire 221-206 BC

Other synonyms of Singan include Changan, Hsian, Xi'an, Xian.

Singan (noun)	Sian (noun)
a city of central China; capital of ancient Chinese empire 221-206 BC	a city of central China; capital of ancient Chinese empire 221-206 BC