yes
A 5-sided shaped solid is called a pentagon in Geometry. It can either be a simple or a self-intersecting pentagon.
A pentagon-based pyramid
yes
A pentagon
A square pyramid has 5 sides.
A pentagon
A pentagon? A solid triangular bar?
pentagon
A triangle, square or pentagon.
A triangle, square or pentagon.
A pentagonal pyramid.
A 3D pentagon could be called a pentagon prism or a dodecahedron which is a Platonic solid with 12 pentagonal faces.