The san in sanqu refers to the detached status of the qu lyrics of this verse form: in other words, rather than being embedded as part of an opera performance the lyrics stand separately on their own. Since the Qu became popular during the late Southern Song Dynasty, and reached a special height of popularity in the poetry of the Yuan Dynasty, therefore it is often called yuanqu (元曲), specifying the type of qu found in Chinese opera typical of the Yuan Dynasty era. Both sanqu and ci are lyrics written to fit a different melodies, but sanqu differs from ci in that it is more colloquial, and is allowed to contain chenzi (襯字 "filler words" which are additional words to make a more complete meaning). Sanqu can be further divided into xiaoling (小令) and santao (散套), with the latter containing more than one melody.
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