What is AAA game category?

Can you explain to me, in simple terms, what exactly the AAA game category entails? I've heard it mentioned frequently in the gaming world, but I'm still a bit hazy on the specifics. Are AAA games simply the most visually stunning and technically advanced games on the market, or is there more to it than that? I'm curious to know what sets these games apart from others in the industry and why they are so highly regarded by gamers and developers alike.