What is the meaning of "Erxin" in Shuo Wen Jie Zi Zhu?

I don't know which word you are talking about. Duan Yucai often uses "two common aspirations" when explaining some river names. For example, the word "Yuan" and "Drowning" in the Ministry of Water Affairs (see the lower column on page 520 of Notes on Interpreting Characters in Shanghai Ancient Books Publishing House).

The so-called "two records" refers to the "geographical records" in the two historical books of Hanshu and Houhanshu. Duan Yucai quoted historical books to explain river basins or changes. If two history books are the same, Duan Yu said that "two records are the same". Duan Yucai, also known as Pre-Chronicle, is called Semi-knowledge, namely Geography of Han History, and Post-Chronicle is Ye Fan's Geography of Han History.