A hexahedron.
Which may also be known as a pentagonal pyramid.
Although it could also be a horizontal pentagon with a vertical pentagonal band formed by ten triangles (aternately facing up and down), topped by five trianles meeting at an apex: a 16-faced polyhedron. Or, of course, it could have two bands of vertical facing triangles - making a 26-hedron, etc.
it's a pyramid with 5 sides.
Triangular based pyramid
triangular cone
a triangular prism.
A pentagon
pyramid
pentagonal pyramid
it's a pyramid with 5 sides.
A pentagon-based pyramid
It is a pyramid
A triangular prism.
Four triangular faces.
A Triangular Prism
Triangular based pyramid
Triangular prism.
a triangular prism!
triangular cone