naphthol

[ naf-thawl, -thol, nap- ]

nounChemistry.

either of two isomeric hydroxyl derivatives, C10H7OH, of naphthalene (alpha-naphthol, or 1-naphthol, and beta-naphthol, or 2-naphthol ), white or yellowish crystals, with a phenolic odor, that darken on exposure to light: used chiefly in dyes, drugs, perfumes, and insecticides.

Origin of naphthol

First recorded in 1840–50; naphth- + -ol¹

Also called hydroxynaphthalene.

Words Nearby naphthol

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use naphthol in a sentence

The substance has the characteristic appearance, odor and taste of naphthol.
The Propaganda for Reform in Proprietary Medicines, Vol. 1 of 2 | Various
This was observed when 6-amino-2-phenylbenzoselenazole was diazotized and coupled with B-naphthol, salicylic acid, etc.
Synthesis of 2-methyl-4-selenoquinazolone, 2-phenylbenzoselenazole, and its derivatives | Y-Gwan Chen
The compounds formed are brilliant orange dyes, the latter being still largely consumed as “naphthol orange.”
Coal | Raphael Meldola
Their discovery not only increased the consumption of beta-naphthol, but also that of the bases which were used for diazotising.
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

British Dictionary definitions for naphthol

naphthol

/ (ˈnæfθɒl, ˈnæp-) /

noun

a white crystalline solid having two isomeric forms, alpha-naphthol, used in dyes, and beta-naphthol, used in dyes and as an antioxidant. Formula: C 10 H 7 OH

Origin of naphthol

C19: from naphtha + -ol 1

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

Scientific definitions for naphthol

naphthol

[ năf′thôl′, -thōl′, năp′- ]

A poisonous organic compound occurring in two isomeric forms. Both isomers are important in the manufacture of dyes, and also in making antiseptics, insecticides, and tanning agents. Naphthol consists of a hydroxyl group (OH) attached to naphthalene. Chemical formula: C10H8O.

Browse