* Heptagon: A polygon with seven sides.
* Heptameter: A line of verse containing seven metrical feet.
* Heptachord: A musical scale with seven notes.
* Heptahedron: A polyhedron with seven faces.
* Heptad: A group of seven.
* Heptalogy: A work consisting of seven parts.
* Heptalite: A rare mineral composed of a heptahydrate.
* Heptavalent: Having a valency of seven.
* Heptahydrate: A compound with seven water molecules per formula unit.
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