isonicotinic acid

noun

iso·nic·o·tin·ic acid ˌī-sō-ˌnik-ə-ˌtin-ik-, -ˌtēn-

: a crystalline acid C₆H₆NO₂ used chiefly in making isoniazid

Cite this Entry

Style

“Isonicotinic acid.” Merriam-Webster.com Medical Dictionary, Merriam-Webster, https://www.merriam-webster.com/medical/isonicotinic%20acid. Accessed 8 Jul. 2026.

Copy Citation

More from Merriam-Webster

Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.

Can you solve 4 words at once?

Word of the Day

gambol

See Definitions and Examples »

Get Word of the Day daily email!

Popular in Grammar & Usage

Is that lie 'bald-faced' or 'bold-faced'?

'A' or 'an'? What about before 'h'? An Indefinite Article Guide

Why is '-ed' sometimes pronounced at the end of a word?

Commonly Misspelled Words

How to Use Em Dashes (—), En Dashes (–) , and Hyphens (-)

Popular in Wordplay

isonicotinic acid

noun

Browse Nearby Words

Cite this Entry

More from Merriam-Webster

Can you solve 4 words at once?

Can you solve 4 words at once?

Word of the Day

gambol

Popular in Grammar & Usage

Is that lie 'bald-faced' or 'bold-faced'?

'A' or 'an'? What about before 'h'? An Indefinite Article Guide

Why is '-ed' sometimes pronounced at the end of a word?

Commonly Misspelled Words

How to Use Em Dashes (—), En Dashes (–) , and Hyphens (-)

Popular in Wordplay

14 Phobias You Probably Haven't Heard Of

The Longest Long Words List

One-Word Oxymorons: Bittersweet, Spendthrift, and More

Ten Words Ending with a Silent ‘T’

12 Lovely and Unusual Words for the Natural World

Popular

Is that lie 'bald-faced' or 'bold-faced'?

14 Phobias You Probably Haven't Heard Of

The Longest Long Words List

Games & Quizzes