A factory mark is a marking affixed by manufacturers on their productions in order to authenticate them. Numerous factory marks are known throughout the ages, and are essential in determining the provenance or dating of productions.

A hallmark is an official mark or series of marks struck on items made of metal, mostly to certify the content of noble metals—such as platinum, gold, silver and in some nations, palladium. In a more general sense, the term hallmark can also be used to refer to any distinguishing mark.