In a design system, tokens are a set of variables that define the visual properties of design elements such as colors, typography, spacing, and more. Tokens are used to ensure consistency and maintain a cohesive look and feel across all design assets. By defining these variables in a centralized location, it becomes easier to make global changes to the design system and ensure that all elements are updated accordingly. Tokens can also be shared across teams and projects, making it easier to maintain a consistent brand identity.