A4D meaning in Internet ?

Affordance is what the environment offers the individual. James J. Gibson coined the term in his 1966 book, The Senses Considered as Perceptual Systems, and it occurs in many of his earlier essays (e.g.). However, his best-known definition is taken from his seminal 1979 book, The Ecological Approach to Visual Perception:

The affordances of the environment are what it offers the animal, what it provides or furnishes, either for good or ill. The verb to afford is found in the dictionary, the noun affordance is not. I have made it up. I mean by it something that refers to both the environment and the animal in a way that no existing term does. It implies the complementarity of the animal and the environment.

The word is used in a variety of fields: perceptual psychology, cognitive psychology, environmental psychology, industrial design, human–computer interaction (HCI), interaction design, user-centered design, communication studies, instructional design, science, technology and society (STS), sports science and artificial intelligence.