naphthol

[naf-thawl, -thol, nap-]

noun Chemistry.

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.

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for naphthol

Historical Examples of naphthol

Various additions have been made from time to time to the naphthol bath.
The Dyeing of Cotton Fabrics
Franklin Beech
When a good method for making the naphthol was discovered in 1869, the dye was made from this.
Coal
Raphael Meldola
Both the formaldehyde and the naphthol exercise tanning actions, but the process is not used in practise.
Principles and Practice of Fur Dressing and Fur Dyeing
William E. Austin
The compounds formed are brilliant orange dyes, the latter being still largely consumed as “naphthol orange.”
Coal
Raphael Meldola
When this compound is combined with naphthol diazo-azo dyes are produced.
The Dyeing of Cotton Fabrics
Franklin Beech

British Dictionary definitions for naphthol

naphthol

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

Word Origin for 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

naphthol in Medicine

naphthol

[năf′thôl′, -thōl′, năp′-]

n.

An organic compound occurring in two isomeric forms, alpha-naphthol and beta-naphthol.naphthalenol

naphthol in Science

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.