Questions relating to making your Sitecore websites easier to use for people with disabilities.
Wikipedia defines accessibility as "the inclusive practice of removing barriers that prevent interaction with, or access to websites, by people with disabilities. When sites are correctly designed, developed and edited, all users have equal access to information and functionality."
More detail about what this covers is available in this article: https://en.wikipedia.org/wiki/Web_accessibility
Commonly this refers to implementing your sites with reference to the Web Content Accessibility Guidelines published by the W3C: https://www.w3.org/WAI/intro/wcag