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heptagon

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

noun

  1. a polygon having seven angles and seven sides.


heptagon British  
/ ˈhɛptəɡən /

noun

  1. a polygon having seven sides

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

heptagon Scientific  
/ hĕp′tə-gŏn′ /
  1. A polygon having seven sides.


Other Word Forms


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.

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Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

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

Many of its component units would go down, but it would go on—and on and on until every hexan trace had disappeared or until the last Vorkulian heptagon had been annihilated.

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

Then, the walls unresisting, he cut in the vastly larger, but infinitely less powerful, I-P ray, and with it systematically riddled the immense heptagon.

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

Any child can make a heptagon at once, notwithstanding Mr. Abbott calls it so difficult.

From The Atlantic Monthly, Volume 05, No. 28, February, 1860 by Various

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