A disability in web accessibility terms is a condition or barrier that limits a person from interacting with or accessing information or functionality of a web application. Disabilities may be permanent, temporary, or situational. It is estimated that approximately 1 in 5 people have a disability. Disabilities are generally classified into 4 areas.
[[File:a11y-disability.png|thumb|none|alt=four disability classifications: Visual, Hearing, Movement, Cognitive|500px|The four disability classifications (Visual, Hearing, Movement, Cognitive)]]
===Visual===