‘Tong’, a term commonly used in ancient Chinese dictionaries, is also widely used in Korean Chinese dictionaries. Through the study of the term in Jeonwun Okpyeon, this paper finds that the term is mainly used to define the characters with the same or close relationship in pronounciation. This is similar to the term in ancient Chinese annotations and dictionaries. However, the term in Jeonwun Okpyeon can also be used to define the situation in which Chinese characters’ shapes and meanings are interlinked. It is, in fact, desirable that the characteristic as such be paid special attention to in the study into ancient dictionary styles of both China and Korea. Based on the exhaustive investigation and analysis of “Tong” in Jeonwun Okpyeon, the paper obtains various types of ‘Tong’, which provides support for the determination of its connotation as well.