**A seven-sided shape is called a heptagon.** A heptagon is one type of polygon, which can have any number of sides.

A polygon is defined as a two-dimensional or plane figure that consists of line segments, which are called edges or sides. The points at which the segments meet are called vertices or corners. Additionally, only two sides meet at each corner of a polygon.

There are five types of polygons:

- Concave: has at least one angle that measures more than 180 degrees; a straight line drawn through the shape intersects more than two segments
- Convex: all angles measure less than 180 degrees; a straight line drawn through the shape intersects no more than two sides
- Equiangular: all angles are equal
- Equilateral: all the segments are the same length
- Regular: polygon is both equiangular and equilateral

A seven-sided polygon is called a heptagon. Polygon names are derived from the Greek language and are formed by using a prefix based on the Greek and adding it to the suffix "gon."

Polygons can have nearly an infinite number of sides, where the letter n represents the number of sides and the word is written "n-gon." For example, a polygon with 47 sides would be written as 47-gon. Another naming convention for polygons with more than 20 sides involves using the Greek prefix for the tens digit, plus "kai," which is the Greek for "and," plus the single digit, and finally the suffix "gon," which would make a 47-sided polygon a tetracontakaiheptagon.