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[naf-thuh-leen, nap-] /ˈnæf θəˌlin, ˈnæp-/
noun, Chemistry.
a white, crystalline, water-insoluble hydrocarbon, C 1 0 H 8 , usually obtained from coal tar: used in making dyes, as a moth repellant, etc.
Also, naphthaline, naphthalin
[naf-thuh-lin, nap-] /ˈnæf θə lɪn, ˈnæp-/ (Show IPA)
Also called tar camphor.
Origin of naphthalene
First recorded in 1865-70; naphth- + -al3 + -ene
Related forms
[naf-thal-ik, nap-] /næfˈθæl ɪk, næp-/ (Show IPA),
[naf-thuh-len-ik, nap-] /ˌnæf θəˈlɛn ɪk, ˌnæp-/ (Show IPA),
adjective Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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Examples from the Web for naphthalene
Historical Examples
  • The important constituents of this portion are carbolic acid and naphthalene.

    Coal Raphael Meldola
  • As aniline is to benzene, so are the naphthylamines to naphthalene.

    Coal Raphael Meldola
  • The story of naphthalene is summarized in the schemes on pp. 164, 165.

    Coal Raphael Meldola
  • It is possible to start from benzene, toluene or naphthalene.

    Creative Chemistry

    Edwin E. Slosson
  • An excess of naphthalene should also be avoided, since, on account of its strong odour, soaps containing much of it are unpopular.

  • naphthalene also begins to show in quantity in the tar as soon as the yield of gas reaches 10,000 cub.

  • Owing to the structure of the naphthalene molecule there are two isomeric naphthols, whereas there is only one phenol.

    Coal Raphael Meldola
  • Other colouring-matters of the same group are in use; some of them, like “new blue,” being derivatives of naphthalene.

    Coal Raphael Meldola
  • It is an amido-derivative of a sulpho-acid of beta-naphthol, so that naphthalene is the generating hydrocarbon of this substance.

    Coal Raphael Meldola
  • He found that by acting on naphthalene—the moth-ball stuff—with chlorine he got a series of useful products called "halowaxes."

    Creative Chemistry

    Edwin E. Slosson
British Dictionary definitions for naphthalene


/ˈnæfθəˌliːn; ˈnæp-/
a white crystalline volatile solid with a characteristic penetrating odour: an aromatic hydrocarbon used in mothballs and in the manufacture of dyes, explosives, etc. Formula: C10H8
Derived Forms
naphthalic (næfˈθælɪk; næp-) adjective
Word Origin
C19: from naphtha + alcohol + -ene
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for naphthalene

1821, coined by English chemist John Kidd (1775-1851), who first isolated and studied it, from naphtha + chemical suffix -ine (2) + -l- for the sake of euphony.

Online Etymology Dictionary, © 2010 Douglas Harper
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naphthalene in Medicine

naphthalene naph·tha·lene or naph·tha·line (nāf'thə-lēn', nāp'-) or naph·tha·lin (-lĭn)
A toxic carcinogenic hydrocarbon derived from coal tar or petroleum and used as a solvent.

naph'tha·len'ic (-lěn'ĭk) adj.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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naphthalene in Science
A white crystalline compound made from coal tar or petroleum and used to make dyes, mothballs, explosives, and solvents. Naphthalene consists of two benzene rings fused together. Chemical formula: C10H8.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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