Merriam-Webster Logo
SINCE 1828
Menu
×

An Encyclopædia Britannica Company

Medical Dictionary

fifth ventricle

noun

Medical Definition of fifth ventricle

  1. :  a cavity between the vertical lamina of the septum pellucidum that does not have a channel of communication with the other ventricles of the brain

Explore M-W

alt-5978cb55e8ba5
The Grammatical History of 'Awaken'/'Awoken'/'Awakened'
emoji-the-quiz
The Emoji Quiz
image1358596246
Words About Word Play
alt-5978a79b75e17
Trending: 'Transgender' Americans Face New Restrictions

Seen and Heard

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

show hide

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

WORD OF THE DAY

fester

play

to become worse as time passes

Get Word of the Day daily email!

TRENDING NOW

  1. transgender Trump reverses military policy allowing transgender people to serve

  2. beleaguer 'Being subjected to constant or repeated trouble or harassment'

  3. scaramouch A new White House communications director

  4. non sequitur “It does not follow”

  5. admiral's mast A massive search ends with an 'admiral's mast'.

SEE ALL

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

Words at Play

alt-5978cb55e8ba5
The Grammatical History of 'Awaken'/'Awoken'/'Awakened'

Or you can just go back to bed.

alt-59775cb5d7779
Words We're Watching: 'Aquafaba'

Don't dump out the bean water just yet...

image1358596246
Words About Word Play

Don't just eat your words—play with them!

alt-596f95fe451e7
'Drought' & 'Drouth' Take Us Back In Time

A variant spelling with a long history

Ask the Editors

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'

payday
How Often Is 'Biweekly'?

Don't get us started on 'bimonthly'

video-irregardless-grammar-peeve-blend-of-the-synonyms-irrespective-and-regardless
Irregardless

It is in fact a real word (but that doesn't mean you should use it).

video-moose-goose-weird-plurals
Weird Plurals

One goose, two geese. One moose, two... moose. What's up with that?

Word Games

emoji-the-quiz
The Emoji Quiz

Think you’re an emoji 👓 expert? Let’s see 🤔

Take the quiz
image941935269
A Game of Thrones Word Quiz

In the Game of Thrones quiz, you learn some new vocabulary. (It’s quite safe, really. You will not die.)

Take the quiz
How Strong Is Your Vocabulary?
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

Take the quiz
Word Winder's CrossWinder
Word Winder's CrossWinder

A game of winding words.

Play the game