A shape with one corner is a triangle. Yes, I know, technically it has three sides, but it only has one corner. So, there you have it, a triangle is the shape you're looking for.
Chat with our AI personalities
Many 3d shapes have a corner.
The corner on a shape where edges meet is called a vertex.
vertex
You connect the points that it has, corner to corner and count them. Moo
Vertex or in plural, vertices