No, a cone is not considered a polyhedron.
A polyhedron is a three-dimensional shape that is made up of flat polygonal faces, straight edges, and vertices. Examples of polyhedra include cubes, pyramids, and octahedrons. Each face on a polyhedron must be a polygon, and the shape must be closed with no curved surfaces.
A cone, on the other hand, has a circular base and a curved surface that tapers up to a point (the apex). The presence of this curved surface disqualifies the cone from being classified as a polyhedron. Therefore, while both cones and polyhedra are three-dimensional shapes, they belong to different categories of geometric figures.