You can name the sides any way you like.
nonacontagon
Hexagons
113
It means many sides
pentagon
Shapes with straight sides are called polygons
a quadrilateral, or Tetragon, or Quadrangle
Regular polygons.
nonagon(also called an enneagon)
There are infinitely many polygons so it would be impossible to name them all. For the names of those with a fewer sides see the related link.
There is no collective name for the infinite family of polygons with more than 8 sides.