An affordance is a resource or support that the environment offers an animal; the animal in turn must possess the capabilities to perceive it and to use it.— Eleanor J. Gibson et al.
* Gibson 1986 – The ecological approach to visual perception ** Subject Index, p. 322 *** Affordance, 127–143 **** concept, introduced, 36
plural affordances merriam-webster 
: the quality or property of an object that defines its possible uses or makes clear how it can or should be used