Xu Collection, Upper Volume
Radical: Metal (jīn)
Sa
Kangxi strokes: 20
Page 1321, Entry 22
Broad Rhymes (Guangyun): Pronounced san (third tone). Jiyun: Pronounced san (third tone). The mechanism of a crossbow being loose.
Also, Jiyun: Pronounced san (third tone). Refers to a crossbow.
Also, Collection of Character Rectification (Zhengzitong): There is an opinion that a crossbow does not carry the name sa, and that sa should be pronounced xian (fourth tone). In current common usage, castrating a rooster is called sa, carrying the same meaning as castrating a bull, a pig, or a horse. Guo Shikong mistakenly wrote sa as xian; this related discussion is found in Miscellaneous Notes from the Jian Studio (Jianzhai suozhuilu). The older annotation gave the pronunciation as san, which is incorrect. In the Elbow-side Manual of the Lean Immortal (Quxian zhouhou jing), it is written as dui. Using sa for a rooster is an instance of a common vernacular character being created by adding a component.