Oh, dude, a shape that has 8 letters? Let me think... Oh, I got it! An octagon! You know, like a stop sign or a really fancy Pizza slice. Eight sides, eight letters, easy peasy.
heptagon
circle
It is polygon but this type of shape is a nonagon.
The Shape That Has 8 Sides Is A Octagon Which Has 8 Equal Sides
Rhombus Hexagon Octagon Nonagon Decagon all have 7 letters
heptagon
octahedron - a polyhedron with 8 faces
octahedron * * * * * OCTAHEDRON has 8 letters??? I make it 10. How about TRIANGLE?
They are polygons
There are a great many of them. One nice one is the icosahedron, which has 20 vertices and 11 letters.
A rhomboid, possibly. The names of 3-d shapes with plane faces end in the suffix -hedron. If the name is to have 8 letters, that leaves only 2!
circle
DODECAHEDRON
A letter cannot have "8 letters" in it.
There is no such shape.
A shape that has a name consisting of seven letters could be a hexagon. A hexagon is a six-sided polygon.
A 2D shape that has four sides and is thirteen letters long is a quadrilateral.