Name of Geometric Shapes

Indicate to dCode the number of sides and it will find the name.

More generally, polygons are written with a prefix indicating their number of sides and the suffix -gon.

Here is the list as a table of all the different regular geometric shapes of the 2D plane (table of n-sided polygon names):

#	Name of the Polygon + Geometric Drawing
1 side	monogon (impossible figure in Euclidean geometry)
2 sides	digon
3 sides	triangle or trigon
4 sides	quadrilateral or quadrangle or tetragon
5 sides	pentagon
6 sides	hexagon
7 sides	heptagon (wrongly septagon)
8 sides	octogon
9 sides	enneagon (ou nonagon)
10 sides	decagon
11 sides	hendecagon
12 sides	dodecagon
13 sides	tridecagon
14 sides	tetradecagon
15 sides	pentadecagon
16 sides	hexadecagon
17 sides	heptadecagon
18 sides	octadecagon
19 sides	enneadecagon
20 sides	icosagon
21 sides	henicosagon
22 sides	doicosagon
23 sides	triaicosagon
24 sides	tetraicosagon
25 sides	pentaicosagon
26 sides	hexaicosagon
27 sides	heptaicosagon
28 sides	octaicosagon
29 sides	enneaicosagon
30 sides	triacontagon
31 sides	hentriacontagon
32 sides	dotriacontagon
33 sides	tritriacontagon
34 sides	tetratriacontagon
35 sides	pentatriacontagon
36 sides	hexatriacontagon
37 sides	heptatriacontagon
38 sides	octatriacontagon
39 sides	enneatriacontagon
40 sides	tetracontagon
50 sides	pentacontagon
60 sides	hexacontagon
70 sides	heptacontagon
80 sides	octacontagon
90 sides	enneacontagon
100 sides	hectogon
200 sides	dihectogon
300 sides	trihectogon
400 sides	tetrahectogon
500 sides	pentahectogon
600 sides	hexahectogon
700 sides	heptahectogon
800 sides	octahectogon
900 sides	enneahectogon
1000 sides	chiliagon
10000 sides	myriagon
1000000 sides	megagon
infinite number of sides	circle

Indicate the number of faces and it will find the name of the 3D geometrical figure.

Here is a table of all the regular geometric shapes/polyhedron of 3D space (table of names of n-faced polyhedra):

#	Name of the Shape (Drawing)
1 face	monohedron
2 faces	dihedron
3 faces	trihedron
4 faces	tetrahedron
5 faces	pentahedron
6 faces	hexahedron
7 faces	heptahedron
8 faces	octohedron
9 faces	enneahedron
10 faces	decahedron
11 faces	hendecahedron
12 faces	dodecahedron
13 faces	tridecahedron
14 faces	tetradecahedron
15 faces	pentadecahedron
16 faces	hexadecahedron
17 faces	heptadecahedron
18 faces	octadecahedron
19 faces	enneadecahedron
20 faces	icosahedron
21 faces	henicosahedron
22 faces	doicosahedron
23 faces	triaicosahedron
24 faces	tetraicosahedron
25 faces	pentaicosahedron
26 faces	hexaicosahedron
27 faces	heptaicosahedron
28 faces	octaicosahedron
29 faces	enneaicosahedron
30 faces	triacontahedron
31 faces	hentriacontahedron
32 faces	dotriacontahedron
33 faces	tritriacontahedron
34 faces	tetratriacontahedron
35 faces	pentatriacontahedron
36 faces	hexatriacontahedron
37 faces	heptatriacontahedron
38 faces	octatriacontahedron
39 faces	enneatriacontahedron
40 faces	tetracontahedron
50 faces	pentacontahedron
60 faces	hexacontahedron
70 faces	heptacontahedron
80 faces	octacontahedron
90 faces	enneacontahedron
100 faces	hectohedron
200 faces	dihectohedron
300 faces	trihectohedron
400 faces	tetrahectohedron
500 faces	pentahectohedron
600 faces	hexahectohedron
700 faces	heptahectohedron
800 faces	octahectohedron
900 faces	enneahectohedron
1000 faces	chiliahedron
10000 faces	myriahedron
1000000 faces	megahedron
infinite number of faces	sphere

Some resources for children are great to learn shapes and other geometric figures such as here (link)

All regular polygons have at least one axial symmetry.

A regular polygon with as many axes of symmetry as it possesses sides.

The axes of symmetry pass through the center of the polygon and the center of each side or each vertex/corner.

All regular polygons with an even side number have a central symmetry (the center of the polygon). Polygons with an odd number of sides have no central symmetry.

A polytope is the generalization of a polygon / polyhedron to all dimensions.