edge
A 3D semi circle
A cone perhaps?
A cone.
it if called a edge for a 3D shape
edge
An edge.
A 3D semi circle
An impossible shape!
CONE
Cylinder
A cone perhaps?
A cone.
it if called a edge for a 3D shape
you call it a edge
2D shape = Decagon 3D shape = Decahedron
nonahedron