What concept refers to the visual clues that indicate how a product or control should be used?

The concept that refers to visual clues indicating how a product or control should be used is affordances. Affordances are potential actions that an object or interface allows, and they are often conveyed through design elements that suggest their function. For example, a button that appears raised may suggest that it can be pressed, while a handle that protrudes invites pulling. These visual cues help users understand how to interact with various components in an intuitive manner.

In contrast, conventions refer to established norms or standard practices in design that users have learned over time, such as the use of red for stop signs. Predictability relates to how expected outcomes follow certain actions within an interface, which is more about the user’s understanding than the immediate visual cues. Micro rules involve specific, smaller design principles that guide usability and interface behavior, but they don't encapsulate the broader idea of visual cues indicating functionality like affordances do.