Merriam-Webster Logo
SINCE 1828
Menu
dictionary thesaurus

phenobarbital

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

Definition of phenobarbital

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

See phenobarbital defined for kids

First Known Use of phenobarbital

1919

in the meaning defined above

See Words from the same year
NEW! Time Traveler

Medical Dictionary

phenobarbital

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

medical Definition of phenobarbital

: 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

cerulean

play

resembling the blue of the sky

Get Word of the Day daily email!

TRENDING NOW

  1. hogwash 'nonsense, balderdash'

  2. probity 'adherence to the highest principles and ideals'

  3. sequacious 'intellectually servile'

  4. inadmissible 'not capable of being allowed'

  5. oligarch, pejorative 'a member a government in which a small group exercises control especially for corrupt and selfish purposes'

SEE ALL

BROWSE DICTIONARY

phenobarbital

Test Your Vocabulary

Difficult Spelling Words Quiz

  • alphabet-pasta-spelling-help
  • Which is the correct spelling?
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

TAKE THE QUIZ
Citation

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

Ask the Editors

Word Games