Is the numeronym a11y accessible?

I joined a new company and I learned that I essentially got the job due to my past experience working with the British gov making some of their forms more accessible. This was a few years ago. I was added to many chat groups and one of them was a11y. I had no idea what it meant. I figured it was about accessibility since they were sharing articles regarding this subject. Anyway, after a bit of mental work, I figured it was short/tech/dev speak for accessibility. I still wasn't sure, though, because the next day, while having coffee, suddenly I thought ALLY! So I had to Google it and I learned what a numeronym was.

TLDR: is the a11y numeronym accessible? I was just chuckling like a weird nerd in the office about this... I don't think it would pass WCAG AAA 3.1.3 Unusual Words:

Blockquote Certain disabilities make it difficult to understand nonliteral word usage and specialized words or usage. Certain disabilities make it difficult to understand figurative language or specialized usage. Providing such mechanisms is vital for these audiences. Specialized information intended for non-specialist readers is encouraged to satisfy this Success Criterion, even when claiming only Single-A or Double-A conformance. Blockquote

I just thought a11y was completely unnecessary... And funny... I'd take this debate to Twitter but I deleted my account.