It means marking identification; a mark used for identification.

Interpretation: ①mark identification, ②mark used for identification.

Source: Ji Kang, Wei, Three Kingdoms, "Soundless Sadness and Music": "The husband's words are not natural and certain things, and they are different from the five directions. They all have different names, so I would like to give a name to identify him." 1 This work is "_knowledge".

Volume 1 of "Zi Che Zhi" written by Guo Tuan of the Song Dynasty: "After dreaming of entering the underworld, the officials were led to a place, which looked like a government office. Both verandas were large houses, filled with money, and each was marked by an official. When asked, he said: 'This is the salary. '"

Song Dynasty Meng Yuanlao's "Tokyo Menghua Lu·Jiaxing Linshui Palace Viewing the Bid Tin Banquet": "Put a red flag in the water in advance to mark it. The land is divided into far and near. "

"Yuan Dian Zhang·Xing Bu IV·Miscellaneous Cases": "The female dog I keep has never bitten anyone, so I have not marked it.