Meta is short for metagame. In videogames, and even in some sports, there are decisions made above/outside of the typical strategy of the game which players call metagame. For example, drafting players in football is metagaming. Or choosing what pickleball paddle to use is metagame.

An expanded view of that is that there's usually a "current" meta strategy that people tend to adhere to, kind of like a convention. And if you stray from that, you lose, even if your strategy would succeed in a vacuum.

For example, if the current meta is for employers to mainly use referrals/networking to hire, it would be a bad strategy to apply to postings.

Thank you! Very helpful clarity, indeed sounds like an incredibly useful term!