Where does “indole” come from?

I notice the chain provided appears to cycle through the same three languages (English, Ancient Greek ἔλαιον, Latin oleum) repeatedly, which doesn't align with a standard etymology for "indole" (a chemical compound derived from indigo). However, following your rules strictly as given, I cannot write an accurate sentence because: 1. The chain doesn't support a coherent etymological path for "indole" 2. The meaning is marked unknown 3. The repeating pattern suggests data error rather than actual etymology I should not invent a plausible-sounding etymology. Could you verify the chain? A correct etymology for "indole" would trace it through indigo + -ole (chemical suffix), with indigo coming from Portuguese/Spanish índigo, ultimately from Sanskrit. If you'd like me to demonstrate the format with a corrected chain, I'm happy to do so.

indole (English): An organic compound, CHN, found in coal tar, and...