Plato is a "flooded" crater that filled with lava after it was created by an impact. A large one. It's floor is relatively flat and largely unscarred (save for a few small craters). A link can be found below for more information.
A large basin shaped crater is called
Caloris Basin (also known as the Caloris Planitia) is an impact crater on Mercury about 1,550 km in diameter, known as the largest crater in the Solar System.
volcanic
The main crater is Caloris Basin.
Caldera .
The usual term is crater. Most craters are nearly circular holes surrounded by rims of ejected material. The term "impact basin" is used for the multiple-ringed structures formed by large impacts.
Impact crater is now more prevalently used for the term impact basin.
Calderas, like Crater Lake, Oregan, USA.
A circular basin surrounded by mountains is typically referred to as a crater or caldera, depending on whether it was formed by volcanic activity or by the collapse of a volcanic cone.
Caloris Basin I think is the deepest and the youngest too.
Recessed area like a crater that is not too deep
There are no craters on Neptune because its made almost entirely of gases.