A Pyramid is a 7 lettered 3D shape with triangular faces.
heptahedron
Pentagonal prism.
a square
Pyramid
Pentagonal prism
Apentagonal prism.
A hexagon based pyramid.
A hexagon based pyramid.
A pentagonal dipyramid.
heptahedron
It cannot be a simply connected 3d shape because it does not satisfy the Euler characteristic.