Affordance

A property of an object or environment that suggests how it can be used, originally defined by psychologist James J. Gibson in 1977 as the actionable possibilities between an actor and their environment. In design, Donald Norman popularised the concept to describe how visual and physical cues communicate functionality to users — a door handle affords pulling, a button affords pressing. In accessibility, affordances are critical because they are often communicated through a single sensory channel: visual cues are inaccessible to blind users, physical affordances may not work for people with motor impairments, and complex affordances may be unclear to people with cognitive disabilities. Accessible design requires that affordances be perceivable through multiple modalities — visual, auditory, tactile — so that all users can understand how to interact with a product or environment.