WCAG (Web Content Accessibility Guidelines)
The W3C standard that defines what makes web content accessible to users with disabilities.
Also called: wcag 2, web content accessibility guidelines
WCAG defines three conformance levels: A (basic), AA (the de-facto industry minimum), and AAA (highest). Most enterprise procurement asks for AA conformance.
The most common failures: insufficient color contrast (especially muted text on light backgrounds), missing keyboard focus indicators, color used as the only signal, and form inputs without labels.