You may have recently seen ‘a11y’ and thought “what is a11y? what does it mean?”. The answer is accessibility. More specifically, it is an abbreviation for the word accessibility. The number 11 represents the number of letters between “a” and “y”.
Why not just type accessibility? It’s used in contexts where character lengths are limited, like Twitter and SMS. On Twitter, you may see some permutations that have airport codes appended to it. For example #a11ybos and #a11ysea are hash tags used by a groups, in Boston and Seattle respectively, who are organizing an Accessibility Camp.