What does Naturally Aspirated mean?

You pretty much have it spot on if the air is going into the engine naturally (not forced by a turbo for example) it is naturally aspirated and the engine is running with normal compression. When a turbo is there running 12psi for example the compression on the engine Is 12psi stronger. The air is being forced into the engine at a higher rate and that’s why it’s forced induction. I’m tired so I may be wrong so someone else feel free to chime in, but I hope this helps

No forced induction= N/A. For example, the Shelby gt350, Lamborghini huracan, and corvette stingray are N/A. Then the Ferrari 488 gtb, corvette c7 z06, and Subaru sti are turboed or supercharged.

Forced induction means there is a mechanism pushing air into the engine. Naturally aspirated is when the engine naturally sucks air into the cylinders.

The aspiration (breathing) of engine is natural aka unassisted

It breathes normally.
All the air coming into the cylinder is because a piston is moving down and essentially sucking it in. Forced induction, ie supercharging, means that air is forced into the cylinders under pressure.

Naturally just means the engine doesn’t have anything added to assist the being sucked in like a “traditional” engine.

You can literally say it about that 09 Camry. If it isn’t being forced in or have an assist to suck it through it is naturally aspritated.

Of course, it’s a bit weird to use that word because an engine is in way natural.

does air from vents count as naturally aspirated?

No turbo or super