dodecagon

American  

[doh-dek-uh-gon, -guhn] / doʊˈdɛk əˌgɒn, -gən /

noun

Geometry.

1. a polygon having 12 angles and 12 sides.

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dodecagon British  

/ dəʊˈdɛkəˌɡɒn, ˌdəʊdɛˈkæɡənəl /

noun

1. a polygon having twelve sides

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Other Word Forms

• dodecagonal adjective

Etymology

Origin of dodecagon

First recorded in 1650–60; dodeca- + -gon

Explanation

A dodecagon is polygon that has twelve sides, just like an octagon has eight sides. The -gon part of dodecagon should clue you in that this is a geometric figure. That leaves the dodeca- part, which means 12. A dodecagon is a polygon, just like a pentagon (five sides) and a hectogon (100 sides). The Greek roots make 12 by combining do (2) and deca (10). This combination of roots can also be found in dodecaphonism (musical composition using the 12-tone technique) and dodecastyle (having 12 columns on a side, which describes certain antique architecture).

Example Sentences

The perimeter of the dodecagon to be inscribed in a circle is greater than the perimeter of the circle.

From A Budget of Paradoxes, Volume I by Smith, David Eugene

In the Arabic pattern on page 276 the dodecagon appears as the basis, and the remarkable powers of the Arab designer are shown in the use of symmetry without employing regular figures.

From The Teaching of Geometry by Smith, David Eugene