: a crystalline alkaloid compound C8H7N that is a decomposition product of proteins containing tryptophan, that can be made synthetically, and that is used in perfumes
also
: a derivative of indole
Examples of indole in a Sentence
Recent Examples on the Web
Glucosinolates are broken down into isothiocyanates (such as sulforaphane) and indoles.
—
Barbie Cervoni, Verywell Health, 11 June 2025
This transition is accompanied by exposure to breast milk, which contains microbes capable of producing indoles.
—Jenny Lehmann, Discover Magazine, 7 Feb. 2025
Under aerobic conditions, in Nairobi for example, paracresol and indole reached concentrations of 89 and 65 μg/g, respectively, which, along with short chain fatty acids such as butyric acid (13 mg/g) explained the strong rancid, manure and farm yard odor.
—Seriously Science, Discover Magazine, 1 May 2014
Tryptophanase breaks down the amino acid tryptophan and produces indole, a chemical that acts like a call to arms.
—Ed Yong, Discover Magazine, 1 Sep. 2010
In bioassays, of the 17 fecal odorants that elicited GC-EAD responses from fly antennae, a blend of indole and one or more of the alcohols phenol, m-/p-cresol and 1-octen-3-ol proved as attractive to flies as canine feces.
—Seriously Science, Discover Magazine, 28 Feb. 2017
This is in part the work of indole, an aromatic compound present in foul-smelling substances like coal tar and feces, which in trace amounts gives the most delicate of flowers an almost animal opulence.
—New York Times, 11 Oct. 2021
In fact, the flower produces dimethyl trisulfide (also found in Limburger cheese and cabbage), trimethylamine (normally released by rotting fish and animals), isovaleric acid (a major component of foot odor) and indole (found in human feces).
—Karl J. P. Smith, Scientific American, 29 July 2016
Like jasmine and gardenia, the flower’s aroma has an under-funk of indole, a molecule that’s also present in (sorry) feces.
—April Long, Town & Country, 13 Sep. 2019
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Barbie Cervoni, Verywell Health, 11 June 2025
This transition is accompanied by exposure to breast milk, which contains microbes capable of producing indoles.
—Jenny Lehmann, Discover Magazine, 7 Feb. 2025
Under aerobic conditions, in Nairobi for example, paracresol and indole reached concentrations of 89 and 65 μg/g, respectively, which, along with short chain fatty acids such as butyric acid (13 mg/g) explained the strong rancid, manure and farm yard odor.
—Seriously Science, Discover Magazine, 1 May 2014
Tryptophanase breaks down the amino acid tryptophan and produces indole, a chemical that acts like a call to arms.
—Ed Yong, Discover Magazine, 1 Sep. 2010
In bioassays, of the 17 fecal odorants that elicited GC-EAD responses from fly antennae, a blend of indole and one or more of the alcohols phenol, m-/p-cresol and 1-octen-3-ol proved as attractive to flies as canine feces.
—Seriously Science, Discover Magazine, 28 Feb. 2017
This is in part the work of indole, an aromatic compound present in foul-smelling substances like coal tar and feces, which in trace amounts gives the most delicate of flowers an almost animal opulence.
—New York Times, 11 Oct. 2021
In fact, the flower produces dimethyl trisulfide (also found in Limburger cheese and cabbage), trimethylamine (normally released by rotting fish and animals), isovaleric acid (a major component of foot odor) and indole (found in human feces).
—Karl J. P. Smith, Scientific American, 29 July 2016
Like jasmine and gardenia, the flower’s aroma has an under-funk of indole, a molecule that’s also present in (sorry) feces.
—April Long, Town & Country, 13 Sep. 2019
Cite this Entry
“Indole.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/indole. Accessed 6 Jul. 2025.
Copy CitationMedical Definition
indole
noun
in·dole
ˈin-ˌdōl 
: a crystalline compound C8H7N that is found along with skatole in the intestines and feces as a decomposition product of proteins containing tryptophan and that can be made synthetically
also
: a derivative of indole
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