A measure of how easily people can use a website to achieve a specified task.
Also, the process of making a website more usable.
Usable websites are easy to learn, intuitive or easy to remember, efficient, free of major errors, and satisfying to use.
If your website is usable, it does what it's supposed to do, helps users achieve their goals, can be used by people with different needs, and can be changed or adapted to achieve new tasks or goals.
Usability matters, because people will leave if they find your website hard to use.
