What term signifies a mark of authenticity?

The term that signifies a mark of authenticity is "cachet." This term is used to denote a mark or seal that indicates a product or item meets certain standards of quality or originality. It often conveys prestige and acceptance within a specific context, such as luxury goods or specialized services. When something is described as having cachet, it suggests that it is recognized and valued for its authenticity and trustworthiness.

In contrast, the other terms have distinct meanings. Emblems represent a symbol or an identifying mark but do not specifically indicate authenticity. Signatures are personal marks indicating identity or approval, rather than a general mark of authenticity. Trademarks are legal protections for brands and products, signifying origin but not necessarily authenticity in a broader sense. Thus, cachet is the most fitting term for a mark that exemplifies authenticity.