Pentagon - Definition, Meaning & Synonyms

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SKIP TO CONTENT pentagon /ˌpɛntəˈgɑn/ /ˈpɛntəgɒn/ IPA guide

Other forms: pentagons

A pentagon is a five-sided polygon: it has one more side than a square.

This is a word you're most likely to learn in math class when studying geometry: a pentagon is a polygon that has five sides. There are many words for shapes that indicate their specific number of sides, such as octagon: a polygon with eight sides. The root penta means "five," which is why a pentagram has five points. You may have heard of the Pentagon, which is the center of the U.S. military in Washington D.C. It has this name because the building has five sides.

Definitions of pentagon

noun a five-sided polygon see moresee less type of: polygon, polygonal shape a closed plane figure bounded by straight sides

Pronunciation US /ˌpɛntəˈgɑn/ UK /ˈpɛntəgɒn/ Cite this entry Style: MLA

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Copy citation DISCLAIMER: These example sentences appear in various news sources and books to reflect the usage of the word ‘pentagon'. Views expressed in the examples do not represent the opinion of Vocabulary.com or its editors. Send us feedback Word Family

Vocabulary lists containing pentagon

Geometry - Introductory

If you feel obtuse when it comes to angles, review this list of geometry terms. You'll learn about planes, polygons, perimeter, and more. It's as easy as pi!

UCPS 6th Grade Roots List #6

#1, #2, #3, #4, #5, #6, #7, #8, #9, #10, #11, #12, #13, #14, #15, #16

Geometry (Base List) MORE VOCABULARY LISTS 2 million people are mastering new words. Master a word

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