Academia

I'm 100% sure that it stands for Three-Letter-Acronym. The joke is that it's an inscrutable business acronym to make fun of inscrutable business acronyms.

I actually used to do this during orientation sessions at my old job. I'd tell the new hires that if they were ever confused by terminology or acronyms, they should never be afraid to ask, because if people are using jargon or TLAs that they don't follow, they will miss the context.

Then I'd pause. If anyone asked what a TLA was, I'd give them a candy bar.