Meaning & use
octagon
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Meanings
nouncountablemathematics
A flat shape with eight straight sides and eight angles.
Grammar: Takes a plural: regular octagons. Often modified by regular, irregular, or convex.
Patterns
- regular octagon
- draw an octagon
- eight-sided octagon
The children drew an octagon by connecting eight equal lines.
A regular octagon has eight equal sides and eight equal angles.
The plaza was built as an octagon with a fountain in the center.
nounusually singularinformalsport
In mixed martial arts, the eight-sided cage or ring used for fights.
Grammar: Usually the Octagon with the, like a name for the competition space.
Patterns
- fight in the Octagon
- enter the Octagon
- Octagon bout
The champion has defended his title in the Octagon three times.
She trained for six months before stepping into the Octagon.
Word forms
| plural | octagons |
|---|
Common combinations
- regular octagon
- A stop sign is shaped like a regular octagon.
- irregular octagon
- The garden path formed an irregular octagon around the trees.
- inside the Octagon
- He became calm as soon as he was inside the Octagon.
Synonyms and how they differ
- eight-sided figure
- A plain descriptive phrase; octagon is the precise geometry term.
Word family
- octagonal adjective
- having eight sides.
- octagonally adverb
- in an eight-sided way; uncommon.
Commonly confused: octagon or octet?
octagon vs octet
An octet is a group of eight, especially musicians; an octagon is an eight-sided shape.
Practice
Which shape has exactly eight straight sides?
Choose one answer.
Octagon comes from the idea of eight and names an eight-sided polygon. Hexagon has six sides, pentagon five, and decagon ten.
Make it your own
Write a sentence using “octagon”, then check it and compare it with the examples above.