In my org, we're technically called Service Reliability Engineers which is internally appropriate and fitting.

I think it's very common knowledge that's what the acronym means. I've never worked at a company that didn't just say SRE

SRE has a lot of different meanings, even in the science & technology world [1]. (I'll refrain from claiming that such is "common knowledge".)

[1] https://en.wikipedia.org/wiki/SRE

Most companies don't have them at all. Not by that name or anything like it, and if they have anyone kinda doing a similar-ish job you'd probably find their role and practices dissimilar enough that you'd not call them that, either.

Never heard of it before.

It's not.

I probably stopped trying to understand what it meant at the 3rd-4th paragraph. I feel I wasn't worth an explanation...

Did you Google it? It's the first thing that comes up.

Google customizes results per the logged in user, so "site reliability engineer" wouldn't necessarily be the first result for different people. Random list: https://www.abbreviations.com/SRE

google made the term popular. there is a book on it that kinda expands on what it entails.