段玉裁在《說文》學研究領域中有著崇高的學術地位，歷來研究段注《說文》者眾，也累積了許多研究成果。余行達先生曾撰〈《說文段注》「未詳」、「未聞」字義探析〉一文，進行探究。惜乎余先生原文及《段注後箋》已毀於文革時期，現存此文乃記憶之殘作。全文僅約兩千餘言，聊舉數例，略記一二，未能完整呈現余先生在此議題之探析原委。本文蒐羅段玉裁書中出現「未聞」注語等相關字例，針對段氏逕云「未聞」而未加說明之例，尋求相關文獻資料加以說明，藉以補段注《說文》之未備，以求在段氏《說文》研究中略盡補充佐證之力。

Qing scholar, Duan Yucai, spent his whole life, editing and revising Xu Shen’s “Shuowenjiezi,” and created 30 chapters of “Annotation of Shuowenjiezi.” Wang Niansun showed high appreciation to this book, saying that, “there has been no such thing for thousands of years since Xu Shen.” Duan has a high academic position in the study of ShuoWen. Many scholars have been studying his work and thus there has always been a lot of research results. It is said that there are about 100 cases of "unheard" in “Annotation of Shuowenjiezi.” Duan sometimes added notes to the “unheard,” while sometimes he did not do so. This paper intends to discuss the word "unheard" in Duan's note, in order to present the viewpoint of Duan's comment and its revision to ShuoWen . In addition, the author intends to seek relevant literature and materials to explain the example of Duan's mark of "unseen" while without any explanation, so as to supplement ShuoWen, in order to contribute to the study of Duan's ShuoWen.