The answer is a septahedron, 11 letter answer
triangular prism
vv
An 11 sided shape is an Eptogon
An 11-sided 3D shape is a hendecahedron.
Tetrahedron
semicircles
a bottomhead
The answer is a septahedron, 11 letter answer
a symmetrical shape
triangular prism
a bottomhead
Ss
I cannot think of any 2-d shape. The 3-d shape with four faces is a tetrahedron.
Septahedron
a isosceles triangle has at least 1 line of symmetry but only has 9 letters
There are a great many of them. One nice one is the icosahedron, which has 20 vertices and 11 letters.