Zuo-za 佐雜 was a general term for subofficial posts during the Qing period 清 (1644-1911), i.e. offices commonly held by unranked subofficial functionaries (li 吏) on the level of districts and prefectures. It is an aggregation of the terms zuo'er 佐貳, shouling 首領, and zazhi 雜職.
The term zuo'er was also used for officials of the local administration that were in a secondary position, such as assistant prefect (tongpan 通判), department vice magistrate (zhoutong 州同) or assistant magistrate (xiancheng 縣丞), but also low functionaries like police officers (xunjian 巡檢) or clerks (dianli 典史).
It was first used in the Jurchen Jin empire 金 (1115-1234) and denoted positions like vice prefect (tongzhi 同知), assistant commissioners (qianyuan 簽院), vice commissioners (fushi 副使), vice governors (shaoyin 少尹), controller-general (tongpan 通判) or aide (cheng 丞).
The post of zazhi was known in the capital administration as well as in the local government. In Beijing, it was used for functions like recorders (zhubu 主簿) and ushers (xuban 序班) of government institutions or commissioners-in-chief (dashi 大使), while in the local administration, the term denoted overseers of the warehouses, granaries, tax collectors, prison warders, heads of courier stations, lock keepers or heads of port authorities.
Other terms to denote the ranks of subofficial functionaries without an official rank were zaliu 雜流 or wei ru liu 未入流.