heptagon

The heptagon is the seven-sided polygon, also known as a septagon.
The heptagon name can be preferred while both the prefix and the suffix are Greek

The regular heptagon is the regular polygon with seven sides.

The regular heptagon cannot be constructed using the classical Greek rules of geometric construction, but it can be done using a Neusis construction.

According to Bankoff and Garfunkel (1973), "since the earliest days of recorded mathematics, the regular heptagon has been virtually relegated to limbo." Nevertheless, Thébault (1913) discovered many beautiful properties of the heptagon.