SINCE 1828

An Encyclopædia Britannica Company

pentahedron

noun pen·ta·he·dron \ ˌpen-tə-ˈhē-drən \

Definition of pentahedron

: a solid bounded by five faces

—

pentahedral

play \ˌpen-tə-ˈhē-drəl\ adjective

Origin and Etymology of pentahedron

New Latin

NEW! Time Traveler

First Known Use: 1590

See Words from the same year

Seen and Heard

What made you want to look up pentahedron? Please tell us where you read or heard it (including the quote, if possible).

show

WORD OF THE DAY

cathexis

play

investment of mental or emotional energy

Words at Play

Words from Letters in the Greek Alphabet

When English borrows from another alphabet

alt-5ada140ed3e28

'Preventive' or 'Preventative'?

alt-5ad8fc71357ed

Words We're Watching: 'Bluebeard,' the Verb

No, it's not a coiffure trend

alt-5ad8d3361fb97

Where 'Cliff-hangers' Come From

You're on the edge of your seat

Ask the Editors

2017 Word of the Year: Behind the Scenes

How we chose 'feminism'

video-title-words-of-the-year-1066

Words of the Year: 1066

Or, Why Pig Meat is Called 'Pork' and Cow Meat is Called 'Beef'

video-literally

Literally

How to use a word that (literally) drives some people nuts.

video-his-or-her

Is Singular 'They' a Better Choice?

The awkward case of 'his or her'

Word Games

Odd Habits and Quirks Quiz

Test your knowledge of strange human behaviors.

Take the quiz

cats-on-impossible-timber

More Confusing Words—Quiz

How many of these commonly confused words do you know?

Take the quiz

True or False?

Test your knowledge - and maybe learn something along the way.

Take the quiz

Word Winder's CrossWinder

Word Winder's CrossWinder

A game of winding words.

Play the game