How is "accessibility" defined in usability principles?

In usability principles, "accessibility" specifically refers to the application's functionality for users with disabilities. This involves ensuring that individuals who may have vision impairments, hearing loss, or other disabilities can effectively use the application. Accessibility includes features such as text-to-speech capabilities, alternative text for images, keyboard navigation, and screen reader support, all of which make digital content usable for people with diverse needs.

Understanding accessibility is crucial for developers and designers as it promotes inclusivity and enhances the user experience for everyone, not just for those without disabilities. This principle is rooted in the belief that technology should be available and usable by all, ensuring that barriers to access are minimized and anyone can interact with the digital environment effectively.