The Zhengzitong 正字通 "Comprehensive [dictionary] of orthodox characters" is a character dictionary whose entries are arranged according to character radicals. It was compiled by Zhang Zilie 張自烈, academician of the Directorate of Education (guozijian 國子監) at the very end of the Ming period 明 (1368-1644). Simply said, the Zhengzitong is an abbreviated form of the dictionary Zihui 字彙, with some errors. It is nevertheless very interesting because it contains quotations from colloquial language that were later not recorded in the famous Qing period 清 (1644-1911) dictionary Kangxi zidian 康熙字典. The Zhengzitong perpetuated the radical system established by the Zihui and was therefore an important milestone on the way to the standard dictionary of premodern China, the Kangxi zidian.
Source: Zhou Shiqi 周女琦 (1988). "Zhengzitong 正字通", in: Zhongguo da baike quanshu 中國大百科全書, Yuyan wenzi 語言文字, p. 517. Beijing/Shanghai: Zhongguo da baike quanshu chubanshe.