a11y = Accessibility

TL;DR: a11y is shorthand for accessibility. Those middle characters are the number one, not lower-case Ls. Say it as A-one-one-Y or A-eleven-Y.


The a11y you may see on Twitter was not invented just to help such a long word fit into a tweet. It, and others, have been around for a long time now.

It is just one variation of a numeronym, a word that can be partially represented by numbers. And while Doctor Who’s robot dog qualifies, as well as the Usenet stain of l33t-speak, in this case we are using the version where letters are replaced.

The word accessibility is thirteen letters long, but when you keep just the a and y, you will have cut eleven (11) letters. That number now goes in the middle and you have a11y.

Some Other Examples

If you work on the web and ever touch anything that crosses borders or languages, then you may recognize these two:


These are common in the translation industry and speak to some specific concepts as a result, so you can read up a bit on their history (which predate the web).

Some Risk


It is not uncommon for people to mistake a11y for the word “ally.” This can happen when typed or spoken. Just like those new to l10n might spell it “lion.”

You can help mitigate this by using a typeface where the number 1 looks different from a lower-case l. Even better, use a typeface where 1 is more than just a vertical line (since “a-pipe-pipe-y” can be just as confusing).

Spell Checkers and Auto-Correct

If you work in this space at all, whether by writing about it, looking for vendors, or being forced to acknowledge it as part of your job, consider adding a11y to your personal or shared dictionary.

While most of us who use it regularly will know what you mean when we see “ally,” we will all be better able to search (and discover it) if you can prevent your tech from making decisions for you.


For years I have worked a slide about a11y into nearly every one of my accessibility talks. If you speak about accessibility, you may want to do the same. Do not assume everyone in the room knows it just because they have chosen to be in that room (especially if they did not choose to be there).

On the Twitters you can see lots of activity if you follow the #a11y hashtag. Other platforms that support tagging typically have a sub-set of users who put the numeronym to use.

Within the industry you may also find folks who pronounce it “ally” and “alley” and who may use those pronunciations in puns for company, product, service, or group names.


I posted a tweet earlier today that you can share to your followers or whomever. I think it is succinct and clear, but I think I am awesome too and that has not borne itself out just yet.

I made a follow-up pun too.


Perhaps if you are really excited about accessibility you can help me lobby for people to adopt a!!y.

Update: November 9, 2017

I often hear people talk about how “unusable” the a11y numeronym is. While I tend to agree there is a barrier to getting it, once you get it the numeronym is invaluable. Even if it keeps getting used in cliched product and service names.

Amanda Rush wrote a piece defending it against one of its detractors:

There are some accessibility issues you could call evergreen. One of them is whether we should use the #a11y or #accessibility hashtag when spreading the good word on the social medias

Update: July 10, 2020

Update: July 15, 2020

Tatiana Mac has converted her explanation from Twitter into a post: #a11y: Accessible or ironic?

Update: August 10, 2020

Eric Bailey has published a11y is web accessibility, which addresses some of the counter-arguments specifically.

I also discovered Dave Sloan wrote a post as well, all the way back in April 2010: Is ‘a11y’ our ally? Thoughts on a tag for web accessibility

Update: June 5, 2022

Back in 2015 Accessibility Now, Inc. registered and received a trademark for the numeronym “A11Y”. Its ownership later changed to Bureau of Internet Accessibility, which is now owned by AudioEye, an accessibility overlay vendor.

The mark consists of standard characters without claim to any particular font style, size, or color. The goods & services claimed for the mark are Providing a web site featuring technology that enables users to comply with website accessibilities [sic] regulations. The application claimed first use as of June 20, 2013.

As I noted above, Dave Sloan wrote a post discussing the existing use of “a11y” in April 2010, well before the claimed first use by AudioEye née Bureau of Internet Accessibility née Accessibility Now.



[…] you know how a11y on Twitter came to stand for accessibility? It’s a numeronym, a word that can be partially represented by […]


[…] a11y = Accessibility – Adrian Roselli – https://adrianroselli.com/2016/11/a11y-accessibility.html […]


Hi Adrian, Infogrid Pacific is updating our publisher production software to handle the new WAI:ARIA spec. and our reading systems AZARDI. I was looking for a suitable article logo and your example stood out. I was going to make a custom one, but your logo and article connect very nicely on this important topic. Mature content never ages!

Would it be possible to use your three line A11Y logo graphic on our Blog article? We will give full credit and a link to this article, or any other article you would like. The blog article is highlighting the problems of A11Y for publisher content and reading systems.

In response to Richard Pipe. Reply

Richard, sure, you can use the image if you follow the Creative Commons Attribution-NonCommercial 3.0 Unported (CC BY-NC 3.0) license. Essentially provide credit, a link, and don’t make it into a logo. Enjoy!

Leave a Comment or Response

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>