- Having seven angles and sides.
- (mathematics, of a number) Belonging to the sequence generated by the formula .
Since 16th century, from heptagon + -al, from Ancient Greek έπτάγωνος (heptagonos).
Variant of heptagon
a plane figure with seven angles and seven sides
Origin of heptagon; from Classical Greek heptagōnos, seven-cornered: see hepta- and amp; -gon