naphthalene

noun

naph·​tha·​lene ˈnaf-thə-ˌlēn How to pronounce naphthalene (audio)
nonstandard ˈnap-
: a crystalline aromatic hydrocarbon C10H8 usually obtained by distillation of coal tar and used especially in organic synthesis

Examples of naphthalene 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.
Mothballs are pesticides commonly made with naphthalene or paradichlorobenzene, which are toxic chemicals. — Karen Brewer Grossman, Southern Living, 1 Jan. 2026 In 1886, two German physicians decided to try naphthalene as a treatment for a patient with worms and a fever; the worms were unfazed, but the fever dropped. — Rivka Galchen, New Yorker, 26 May 2025 Mothballs are pesticide products made from naphthalene or paradichlorobenzene, and, as with any pesticide, certain precautions should be taken and proper instructions need to be followed for success. — Rae Ford, Martha Stewart, 24 May 2026 Orbital Arc’s use of naphthalene aids in their shrinking of product costs, which the company claims is at 25 to 33 percent of traditional Hall thrusters. — Perri Thaler, IEEE Spectrum, 9 Nov. 2025 See All Example Sentences for naphthalene

Word History

Etymology

alteration of earlier naphthaline, irregular from naphtha

First Known Use

1821, in the meaning defined above

Time Traveler
The first known use of naphthalene was in 1821

Rhymes for naphthalene

See All Rhymes for naphthalene

Browse Nearby Words

naphthalated
naphthalene
naphthaleneacetic acid
See all Nearby Words

Cite this Entry

“Naphthalene.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/naphthalene. Accessed 7 Jul. 2026.

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Kids Definition

naphthalene

noun
naph·​tha·​lene ˈnaf-thə-ˌlēn How to pronounce naphthalene (audio)
ˈnap-
: a hydrocarbon in the form of crystals usually obtained from coal tar and used in chemical manufacture and as a moth repellent

Medical Definition

naphthalene

noun
naph·​tha·​lene -ˌlēn How to pronounce naphthalene (audio)
: a crystalline aromatic hydrocarbon C10H8 usually obtained by distillation of coal tar and used especially in organic synthesis and formerly as a topical and intestinal antiseptic
naphthalenic
ˌnaf-thə-ˈlen-ik How to pronounce naphthalene (audio) ˌnap- How to pronounce naphthalene (audio)
-ˈlēn-
adjective

More from Merriam-Webster on naphthalene

Nglish: Translation of naphthalene for Spanish Speakers

Britannica.com: Encyclopedia article about naphthalene

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