What a thing's form tells you it can do. A handle affords pulling; a flat plate affords pushing. Design is mostly this.
Coined in 1966 by psychologist James J. Gibson from AFFORD, from Old English geforthian (to further, to bring forth), with the noun suffix -ance; what a thing's form tells a body it can do.
What a thing's form tells a body it can do, a handle inviting a pull, a plate inviting a push.