An edge.
is called an edge.
A line is.
The line segments that are common to intersecting faces of a polyhedron are called edges. Each edge is formed by the intersection of two faces and serves as a boundary between them. In a polyhedron, edges connect the vertices and help define the overall shape of the three-dimensional figure.
line
A Circle.
The intersection of two lines is a point. If both lines are straight the figure of four separate triangles are formed. The type of triangles are dependent on the angle of the intersection.
Three dimensional space.
A dihedral angle.
An edge.
square
a square
A parabola is the figure formed by the intersection of a circular cone and a plane that lies parallel to the edge of the cone. (the cone does not have to be a right [90°] circular cone).