heterocyclic vs indole

heterocyclic and indole both are nouns.

Word	Noun	Adjective	Verb	Adverb
heterocyclic	Yes	Yes	No	No
indole	Yes	No	No	No

As nouns, indole is a hyponym of heterocyclic; that is, indole is a word with a more specific, narrower meaning than heterocyclic:

heterocyclic: a compound containing a heterocyclic ring
indole: a white or yellowish crystalline heterocyclic compound extracted from coal tar and used in perfumery, medicine, and as a flavouring agent.

Other hyponyms of heterocyclic include chelate, chelate compound, lactide.

heterocyclic (noun)	indole (noun)
a compound containing a heterocyclic ring	a white or yellowish crystalline heterocyclic compound extracted from coal tar and used in perfumery, medicine, and as a flavouring agent.

heterocyclic (adjective)	indole (adjective)
containing a closed ring of atoms of which at least one is not a carbon atom