Some scholars argue that after the Yuan and Ming dynasties, the function of the character "Dai"(埭) gradually diminished in real life, and the character itself slowly faded from people's view. In modern life, people may occasionally encounter the character "Dai"(埭) in some ancient place names or modern place names that inherit ancient traditions. Others suggest that the use of "Dai" (埭) in place names in Wenzhou, Zhejiang Province, is influenced by the Min dialect. However, this paper holds a different view. In fact, in the provinces and cities south of the Yangtze River, including Zhejiang, Shanghai, Jiangsu, Anhui, and Fujian, the character "Dai"(埭) is very common as a place name, with a higher frequency of use compared to its function as a water conservancy facility. It is by no means "occasional." As a frequently used place name, including in Fujian, it has not faded from people's view at all. Through diachronic examination, it is found that the character "Dai"(埭) has been used as a place name at least since before the Tang Dynasty and has never been (埭) interrupted. It was not only used as a place name after the Yuan and Ming dynasties. The toponymic use of 'Dai' (埭) across Zhejiang, Shanghai, Jiangsu, Anhui, and Fujian can be regarded as a vestige of ancient Chinese linguistic heritage. Many dictionaries, including some well-known ones, have not included the meaning of "place name character" for "Dai," which seems inappropriate. These dictionaries have included the dialectal usage of "Dai"(埭) as a measure word but have overlooked its dialectal place name usage, which is a case of "focusing on one thing while neglecting another."