Countermark refers to a mark or symbol impressed onto something to indicate authenticity or source. There are several synonyms for the word countermark. These include hallmark, stamp, seal, emblem, insignia, brand, logo, symbol, trademark, crest, monogram, and badge. A hallmark is a stamp or mark that represents quality, origin, or purity of a product. A symbol is a design or icon that represents an organization or entity. A badge is a metal or cloth emblem worn to indicate rank or membership in an organization. A countermark can be used for security or identification purposes, and its synonyms are essential in defining its function and purpose.