If they are flat two dimensional shapes with three or more sides, they are called polygons.
If they are solid figures, they are called polyhedrons.
The words come from Greek:
Polugonos = many angled
Poluedros - many sided
Both definitions taken from my Concise Oxford English Dictionary.
Shapes with straight sides are called polygons
There are infinitely many 2d shapes. They can have 1 side (a circle or ellipse) to infinitely many. They can have sides that are straight or not, the sides can be equal or unequal in length, the angles can be equal or unequal, etc.
There are many such shapes and there is no specific name.
a triangle
quadrangles No it quadrilaterals
Polygons
They are called sides or edges.
Shapes with straight sides are called polygons
There are infinitely many 2d shapes. They can have 1 side (a circle or ellipse) to infinitely many. They can have sides that are straight or not, the sides can be equal or unequal in length, the angles can be equal or unequal, etc.
They are called heptagons.
They are called hendecagons.
There are many such shapes and there is no specific name.
There are many shapes with 2 parallel sides. These are generally called quadrilaterals, they are shapes like squares, and rectangles. ================================================= ANY shape with more than 3 sides can have 2 parallel ones. Its name depends on how many sides it has in total..
Nonagons.
Hexagon.
a triangle
There are infinitely many of them so it is not possible to list their names. If the sides are all straight lines, they are collectively called polygons.