續一切經音義 2.194

2.194

箜篌（上音空下音侯釋名云此師延所作靡靡之樂也後出於桑間[濮-(仁-二)+彳]上之空地葢空國之侯所存因以為名也）。

箜篌 (The first character is pronounced 空, the second 侯. The Shiming says: 'This decadent music was made by Shi Yan.' Later it emerged in the vacant land between Sangjian and the Puyang River; because it was preserved by a marquis [hou] of a deserted state [kongguo], it was named after him).