An affordance is a concept used in psychology and design to describe the relationship between an individual and their environment or an object. In psychology, affordance refers to what the environment offers the individual, while in design, it refers to the possible actions that an actor can readily perceive. An affordance is not a property of an object, but rather a relationship between the user and the object, and it is defined by the users capabilities. For example, a door affords opening if you can reach the handle, but for a toddler who cannot reach the handle, the door does not afford opening.

Affordances are important for designers because they help determine how an object can be used and how it maps to peoples mental models. Affordances can be perceptible or hidden, and they offer a direct link between perception and action. When affordances are hidden or false, they can lead to mistakes and misunderstandings.

The term "affordance" was coined by psychologist James Gibson in 1977, referring to all action possibilities with an object based on users physical capabilities. Affordances are a key concept for designers who want to build products that are intuitive and easy to use.

In summary, an affordance is a relationship between an individual and their environment or an object, and it is defined by the users capabilities. It is not a property of an object, but rather a characteristic of the relationship between the user and the object. Affordances are important for designers because they help determine how an object can be used and how it maps to peoples mental models.