POUR
Also known as: Perceivable, Operable, Understandable, Robust
POUR is the four core principles WCAG is built on: content must be Perceivable, Operable, Understandable and Robust.
In plain terms
Perceivable means people can sense the content (text alternatives, contrast, captions). Operable means they can use it (keyboard, enough time, no seizures). Understandable means it's clear and predictable. Robust means it works with assistive tech now and in future. Every WCAG checkpoint sits under one of these four.
Why it matters
POUR is a useful mental model. When you hit a tricky design question, ask which principle it touches — it usually points you straight to the relevant checkpoint and fix.
A video fails "Perceivable" without captions, and "Operable" if its player can't be used by keyboard — two different principles, two different fixes.
Related terms
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