The corner on a shape where edges meet is called a vertex.
a vertex
square
A right angle.
A shape that has one corner is a cone.
Many 3d shapes have a corner.
A rhomboid, possibly. The names of 3-d shapes with plane faces end in the suffix -hedron. If the name is to have 8 letters, that leaves only 2!
Wich 3 D shape has a corner on it?
The hexagon has six corners and six sides.
That would usually be referred to as a vertex.
A OctahedronThis shape has 8 faces.
triangle