It’s just short for automatic transmission, opposed to manual transmission. I think Americans call manual cars sticks though. But they’re not sticks, because sticks are wood and cars are almost always metal. Not metal like the music though.
Edit - thinking on it you could play metal through the car stereo though.
I know the difference between an automatic & manual car & transmission. The analogy just doesn’t make sense, because when you say “automatic / manual car” you’re still referring to something within the car, the transmission system - you’re not actually calling the car to be “automated” or whatever. Calling LLMs “AI” however is nothing but a misnomer and that analogy simply does not compare at all.