heptagon

American  

[hep-tuh-gon, -guhn] / ˈhɛp təˌgɒn, -gən /

noun

1. a polygon having seven angles and seven sides.

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heptagon British  

/ ˈhɛptəɡən, hɛpˈtæɡənəl /

noun

1. a polygon having seven sides

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heptagon Scientific  

/ hĕp′tə-gŏn′ /

1. A polygon having seven sides.

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Other Word Forms

• heptagonal adjective

Etymology

Origin of heptagon

First recorded in 1560–70, heptagon is from the Greek word heptágōnos seven-cornered. See hepta-, -gon

Explanation

A heptagon is a polygon with seven sides, just as an octagon has eight sides. With seven sides, a heptagon must be lucky. Triangles and rectangles are two of the most common polygons (enclosed shapes), but there are many more, including the heptagon, a seven-sided polygon. You don't see many of these in nature bigger than molecules, but people have found several uses for this seven-sided figure, most commonly in coins: the British 20p and 50p pieces are both heptagons. The roots are Greek, and this word shares the hept prefix with other seven-related words such as heptad, heptameter, and heptathlete.

Example Sentences

Each interior angle of a regular heptagon is a bit over 128 degrees, so when we put three of them together at a vertex, we get more than 360 degrees.

From Scientific American • Nov. 17, 2013

To give the 50-new-penny coin a distinctive appearance, the Decimal Currency Board designed what it proudly billed as the world's first coin in the shape of "an equilateral curve heptagon."

From Time Magazine Archive

Then all three were lifted lightly into the air, and without a word or a sign were borne through the air-locks of the vessel, and into an opening in the wall of the rescuing heptagon.

From Spacehounds of IPC by Smith, E. E. (Edward Elmer)

The heptagon points out the Encampment destined for the Princes of Libanus, Jerusalem, etc.; and these are to receive their orders from the five Princes.

From The Mysteries of Free Masonry Containing All the Degrees of the Order Conferred in a Master's Lodge by Morgan, William

For I, as mere biographer, have the aid neither of Imperial Chamber nor of Executive-posse against my heptagon; but were I an Imperial Diet they would soon give me many a--promise.

From The Invisible Lodge by Jean Paul