Merriam-Webster Logo
SINCE 1828
Menu
×

An Encyclopædia Britannica Company

phenobarbital

play
noun phe·no·bar·bi·tal \ˌfē-nō-ˈbär-bə-ˌtȯl\

Definition of phenobarbital

  1. :  a crystalline barbiturate C12H12N2O3 used as a hypnotic, sedative, and anticonvulsant

See phenobarbital defined for kids

Explore M-W

alt-5947fc40f1b5c
In Tech, What Does 'K' Mean?
istock-refers-to-this-as-a-tumble-of-strawberries-which-sounded-pretty-nice-to-us
June 2017 Words of the Day Quiz
supreme-court-at-dusk
Trending: SCOTUS: 'Bona Fide' relationships
image599301899
Pretty in 'Pink'

First Known Use of phenobarbital

1919

Medical Dictionary

phenobarbital

play
noun phe·no·bar·bi·tal \ˌfē-nō-ˈbär-bə-ˌtȯl, -tȧl\

Medical Definition of phenobarbital

  1. :  a crystalline barbiturate C12H12N2O3 that is used orally or is administered by injection in the form of its sodium salt C12H11N2NaO3 as a hypnotic and sedative—see luminal

Seen and Heard

What made you want to look up phenobarbital? 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

scapegrace

play

an incorrigible rascal

Get Word of the Day daily email!

TRENDING NOW

  1. bona fide Made in good faith

  2. surrogate mother From TMZ to the dictionary.

  3. zealot A fanatical partisan

  4. stonewall to be uncooperative, obstructive, or evasive

  5. scurrilous Containing obscenities, abuse, or slander

SEE ALL

BROWSE DICTIONARY

phenobarbital

WORD GAMES

Take a 3-minute break and test your skills!

  • istock-refers-to-this-as-a-tumble-of-strawberries-which-sounded-pretty-nice-to-us
  • Which is a synonym of garner?
Spell It

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ
Word Winder's CrossWinder

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ

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-5947fc40f1b5c
In Tech, What Does 'K' Mean?

A buzzword with a long history.

alt-5951697e1a410
When To Use 'Specious' vs. 'Spurious'

These similar words are not interchangeable

alt-594bf2ec5f26e
Quick: Read This!

'Quick' once had a very different meaning

alt-594d2b6325245
'Pride': The Word That Went From Vice to Strength

Do you take pride in Pride?

Ask the Editors

decimate-video
Is it wrong to use 'decimate' to mean 'destroy'?

Language changes

serial-comma
The Serial Comma

Why don't they call it the Merriam-Webster comma?

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

istock-refers-to-this-as-a-tumble-of-strawberries-which-sounded-pretty-nice-to-us
June 2017 Words of the Day Quiz

Summer's first WOTD quiz.

Take the quiz
alt-5941ad7527c3c
Yearbook Superlatives Quiz

Is that your picture under "Largest Vocabulary"?

Take the quiz
Spell It
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