It sounds like the author first says that the word "a11y" is not accessible because it's jargon, but then says that jargon is ok as long as it's defined somewhere. He then proceeds to compare the alternative word "accessibility" with "A11y" and finds they are slightly different in meaning. So it sounds like if we want to use the word "a11y", just make sure it's defined somewhere, and know that there are no exact alternatives. Is that accurate?

Personally a lot of this a11y stuff is complicated and confusing to me. I am trying my best to be a responsible dev, but it feels overwhelming sometimes.