indole

/ˈɪndəʊl/

//ˈɪndəʊl// noun

"indole" is a 6-letter English headword indexed on PlainSpell.

The verdict

“indole” is uncommon English (frequency #67,528 among 17,902 “I” headwords), classed as a noun. The kind of spelling people second-guess.

#67,528
frequency rank, English
17,902
“I” headwords

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - An organic compound, C₈H₇N, found in coal tar, and produced in the gut by the bacterial decomposition of tryptophan; it is an aromatic bicyclic heterocycle having a benzene ring fused with a pyrrol...

Key facts for indole
PropertyValue
Headwordindole
LanguageEnglish
Part of speechNoun
IPA/ˈɪndəʊl/
Letters6
Frequency rank#67,528
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Where “indole” sits in English frequency

Every-word frequency runs from the handful of words we use constantly (left) to the long tail used once in a blue moon (right). indole lands here:

#1#100#1K#10K#100K
← used constantlyrarely used →

Scale is logarithmic (each tick is 10× rarer). Source: FrequencyWords open word-frequency list.

Rare enough to double-check

indole is uncommon English at frequency #67,528 among 17,902 “I” headwords, classed as anoun, transcribed /ˈɪndəʊl/. Rarity is why readers land here mid-draft. 2 senses are on record.

Zero misspellings are on record for indole in our index, a straightforward case of a spelling with little room for common typos. It is not paired with a close-neighbour confusable in our dataset, suggesting its spelling stands apart enough that readers rarely confuse it with something else.

Etymologically, the entry records: From indigo + Latin oleum (“oil”); see -ole. The correct English form is indole, spelled I-N-D-O-L-E.

Definition

  1. 1
    An organic compound, C₈H₇N, found in coal tar, and produced in the gut by the bacterial decomposition of tryptophan; it is an aromatic bicyclic heterocycle having a benzene ring fused with a pyrrole ring; indole and its derivatives occur widely in nature and have many industrial applications.
  2. 2
    Any of the derivatives of indole.

Etymology

From indigo + Latin oleum (“oil”); see -ole.

This word in other languages

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA); frequency ordering uses the FrequencyWords open word-frequency list (2018 English corpus, MIT). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "indole"?
"indole" is spelled I-N-D-O-L-E. The IPA pronunciation is /ˈɪndəʊl/.
What does "indole" mean?
As a noun, "indole" means: An organic compound, C₈H₇N, found in coal tar, and produced in the gut by the bacterial decomposition of tryptophan; it is an aromatic bicyclic heterocycle having a benzene ring fused with a pyrrol...
How do you pronounce "indole"?
The IPA (International Phonetic Alphabet) transcription for "indole" is /ˈɪndəʊl/. Click the speaker icon on the pronunciation badge above to hear it spoken aloud where audio is available.
What is the origin of the word "indole"?
From indigo + Latin oleum (“oil”); see -ole. See the full etymology section above for more details.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Using “indole”

The practical upshot for anyone who landed here from a spell-check.

  • The one correct English spelling is I-N-D-O-L-E - every other letter order is a misspelling in standard orthography.
  • Say it as /ˈɪndəʊl/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
  • Browse more English words and confusable pairs in the same reference. English words

Other uncommon English words near this rank

Data Source

Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list FrequencyWords open word-frequency list