isoniazid

noun

iso·​ni·​a·​zid ˌī-sə-ˈnī-ə-zəd How to pronounce isoniazid (audio)
: a crystalline compound C6H7N3O used in treating tuberculosis

Examples of isoniazid in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Eventually, the trial would determine isoniazid was most effective when used with two other antibiotics. — Emilie Le Beau Lucchesi, Discover Magazine, 8 Feb. 2025 Some of the most common include isoniazid, rifampicin, pyrazinamide and ethambutol. — Melissa Rudy, Fox News, 31 Oct. 2024

Word History

Etymology

is- + nicotinic acid + hydrazide

First Known Use

1952, in the meaning defined above

Time Traveler
The first known use of isoniazid was in 1952

Rhymes for isoniazid

See All Rhymes for isoniazid

Browse Nearby Words

isoniazid
See all Nearby Words

Cite this Entry

“Isoniazid.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/isoniazid. Accessed 23 Mar. 2025.

Copy Citation

Share

Medical Definition

isoniazid

noun
iso·​ni·​a·​zid ˌī-sə-ˈnī-ə-zəd How to pronounce isoniazid (audio)
: a crystalline compound C6H7N3O used in treating tuberculosis

called also isonicotinic acid hydrazide

More from Merriam-Webster on isoniazid

Britannica.com: Encyclopedia article about isoniazid

Last Updated: - Updated example sentences
Love words? Need even more definitions?

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

Popular in Grammar & Usage

See More

The Difference Between 'i.e.' and 'e.g.'

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

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

What's the difference between 'fascism' and 'socialism'?

More Commonly Misspelled Words
See More

Popular in Wordplay

See More

What do SCOTUS, POTUS, and FLOTUS mean?

Flower Etymologies For Your Spring Garden

More Words with Remarkable Origins

Terroir, Oenophile, & Magnum: Ten Words About Wine

8 Words for Lesser-Known Musical Instruments
See More

Popular Features

See More

The Difference Between 'i.e.' and 'e.g.'

What do SCOTUS, POTUS, and FLOTUS mean?

Flower Etymologies For Your Spring Garden
See More

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Word Game Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
Missing Letter A daily crossword with a twist
dog-in-disguise
Rhyme Disguise Quiz Pair up words that look different but sound alike.
See All