SINCE 1828

An Encyclopædia Britannica Company

Medical Dictionary

pars compacta

noun pars com·pac·ta \ -käm-ˈpak-tə \

medical Definition of pars compacta

: the large dorsal part of gray matter of the substantia nigra that is next to the tegmentum

Seen and Heard

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

show

WORD OF THE DAY

bloviate

play

to speak or write verbosely and windily

Words at Play

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

alt-5ad77fad37d22

What the #@*% Is a ‘Grawlix'?

We can thank Beetle Bailey.

alt-5ad76a1542e73

'Altho' vs. 'Although'

Altho doesn't get much love.

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

Spell It

Can you spell these 10 commonly misspelled words?

Take the quiz

Word Winder's CrossWinder

Word Winder's CrossWinder

A game of winding words.

Play the game