Azurian
The Azurian
The Kuiper Belt: think of it as a second asteroid belt, except with comets/icy/frozen objects instead of stony/iron like the asteroids. It's beyond Neptune, and its existence (proven since the 90s) is pretty much the main reason why Pluto got downgraded. Most short-period (orbit < 200 years) comets come from here. Although, it's considerably sparser and larger than the Mars-Jupiter asteroid belt.
The Oort Cloud: Is still hypothesized, yes - at these distances, it's hard to see anything that doesn't emit its own light. It's MUCH MUCH bigger and sparser than the Kuiper belt, and stretches out to pretty much a light year (50K AU) from the Sun. not much is really known about this region beyond that.
But yeah, what the above two people said.
Thank you very much, I was confused on the relationship between the two.

