List of two-dimensional geometric shapes explained

This is a list of two-dimensional geometric shapes in Euclidean and other geometries. For mathematical objects in more dimensions, see list of mathematical shapes. For a broader scope, see list of shapes.

Generally composed of straight line segments

See main article: Polygon.

Polygons with specific numbers of sides

Henagon – 1 side
Digon – 2 sides
Triangle – 3 sides
- Acute triangle
- Equilateral triangle
- Heptagonal triangle
- Isosceles triangle
  - Golden Triangle
- Obtuse triangle
- Rational triangle
- Heronian triangle
  - Pythagorean triangle
  - Isosceles heronian triangle
- Right triangle
  - 30-60-90 triangle
  - Isosceles right triangle
  - Kepler triangle
- Scalene triangle
Quadrilateral – 4 sides
- Cyclic quadrilateral
- Kite
- Parallelogram
  - Rhombus (equilateral parallelogram)
    - Lozenge
  - Rhomboid
  - Rectangle
  - Square (regular quadrilateral)
- Tangential quadrilateral
- Trapezoid
  - Isosceles trapezoid
Pentagon – 5 sides
Hexagon – 6 sides
- Lemoine hexagon
Heptagon – 7 sides
Octagon – 8 sides
Nonagon – 9 sides
Decagon – 10 sides
Hendecagon – 11 sides
Dodecagon – 12 sides
Tridecagon – 13 sides
Tetradecagon – 14 sides
Pentadecagon – 15 sides
Hexadecagon – 16 sides
Heptadecagon – 17 sides
Octadecagon – 18 sides
Enneadecagon – 19 sides
Icosagon – 20 sides
Icosikaihenagon - 21 sides
Icosikaidigon - 22 sides
Icositrigon - 23 sides
Icositetragon - 24 sides
Icosikaipentagon - 25 sides
Icosikaihexagon - 26 sides
Icosikaiheptagon - 27 sides
Icosikaioctagon - 28 sides
Icosikaienneagon - 29 sides
Triacontagon - 30 sides
Tetracontagon - 40 sides
Pentacontagon - 50 sides
Hexacontagon - 60 sides
Heptacontagon - 70 sides
Octacontagon - 80 sides
Enneacontagon - 90 sides
Hectogon - 100 sides
Dihectogon - 200 sides
Trihectogon - 300 sides
Tetrahectogon - 400 sides
Pentahectogon - 500 sides
Hexahectogon - 600 sides
Heptahectogon - 700 sides
Octahectogon - 800 sides
Enneahectogon - 900 sides
Chiliagon - 1,000 sides
Myriagon - 10,000 sides
Megagon - 1,000,000 sides
Star polygon – there are multiple types of stars
- Pentagram - star polygon with 5 sides
- Hexagram – star polygon with 6 sides
  - Star of David (example)
- Heptagram – star polygon with 7 sides
- Octagram – star polygon with 8 sides
  - Star of Lakshmi (example)
- Enneagram - star polygon with 9 sides
- Decagram - star polygon with 10 sides
- Hendecagram - star polygon with 11 sides
- Dodecagram - star polygon with 12 sides
Apeirogon - generalized polygon with countably infinite set of sides

Curved

See main article: List of curves.

Composed of circular arcs

Not composed of circular arcs

Heartagon
Various lemniscates
Oval
Ovoid – similar to an oval
Superellipse
Taijitu
Tomoe
Magatama