noun

indole

IN-dohl

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Indole (noun) means an organic compound found in coal tar and made in the gut when bacteria break down tryptophan. Example: “Indole is a ring-shaped molecule made of a benzene ring joined to a smaller ring.”

noun

An organic compound found in coal tar and made in the gut when bacteria break down tryptophan.

"Indole is a ring-shaped molecule made of a benzene ring joined to a smaller ring."

"Gut bacteria produce indole as they digest the amino acid tryptophan."

"The chemist isolated indole from a sample of coal tar."

Any chemical compound derived from indole.

"Many plant hormones are indoles."

"The lab synthesized several new indoles for testing."

"Researchers study how different indoles behave in the body."

How to use indole

Learner’s notes

In plain EnglishA ring-shaped chemical compound found in coal tar and made by gut bacteria.

When to use it

It is a technical term used mainly in chemistry and biology.

Memory tip

The word is a noun and takes a regular plural, indoles, when it means compounds derived from indole.

Trace the full origin ↓

Common pairings

indole derivative indole ring indole compound indole synthesis

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C2 · Advanced serendipity Fortunate discoveries made entirely by accident.

Gen Z slang rizz Charm — the ability to attract a romantic interest.

B2 · Intermediate empathy The capacity to share another person’s feelings.

C1 · Advanced nonchalant Casually calm and relaxed; unconcerned.

Internet slang delulu Delusional — believing something against the odds.

Etymology nostalgia Greek nostos “return home” + algos “pain”.

C2 · Advanced serendipity Fortunate discoveries made entirely by accident.

Gen Z slang rizz Charm — the ability to attract a romantic interest.

B2 · Intermediate empathy The capacity to share another person’s feelings.

C1 · Advanced nonchalant Casually calm and relaxed; unconcerned.

Internet slang delulu Delusional — believing something against the odds.

Etymology nostalgia Greek nostos “return home” + algos “pain”.

Test yourself on “indole” A quick quiz — meaning, synonyms & usage →

Fill the gap

Can you complete this real example?

_____ is a ring-shaped molecule made of a benzene ring joined to a smaller ring.

Etymology

The word was built from the start of indigo joined to the Latin word for oil, oleum, reflecting the compound's link to the dye indigo.

Origin: English

Synonyms

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ketole

Rhymes for indole

ole hole vole mole sole pole cole dole role stole whole Poole

See all rhymes for indole →

Frequently asked questions

What is indole?

Indole is an organic compound with a benzene ring fused to a pyrrole ring. It occurs in coal tar and is produced in the gut by bacterial breakdown of tryptophan.

How do you pronounce indole?

In American English it is pronounced IN-dohl, with stress on the first syllable.

Where does the word indole come from?

It combines part of the word indigo with the Latin word for oil, oleum.

What is the meaning of indole?

"indole" (noun) means an organic compound found in coal tar and made in the gut when bacteria break down tryptophan.