What the F-ragrance is an Indole?

By Lola,

Indole (adjective indolic) is a chemical compound synthesized but also occuring naturally in floral notes like jasmine and tuberose.  which smells floral at low concentrations, fecal at high concentrations. A very common perfumery term, indoles usually impart a narcotic (strong floral), ripe or animalic character.
As an aside indoles also occur naturally in fecal matter, perhaps giving credence to those who suggest indoles smell a bit like poo. There you have it.

Image reference is Baeyer’s original structure for indole, 1869