1. A plane figure consisting of seven sides and seven angles; a place that has seven bastions for defence.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• petagon,
• geptagon,
• beptagon,
• neptagon,
• jeptagon,
• eptagon,
• heptegon,
• heptagyna,
• heptaech,
• heptagone,
• heptain,
• heptaclor,
• Hematogon,
• heptagan,
• heptogon,
• heptagono,
• hepatogon,
• Heptangol,
• Hopagon,
• Heptagyne

The adjective form of the word "heptagon" is "heptagonal".

The plural of the "heptagon" can be the "heptagons".

The singular of the "heptagon" can be the "heptagon".