isothiazole

The story

1. Ancient Greekῐ̓́σος (ĭ́sos)
2. Englishiso-
3. Proto-Indo-European*dʰewh₂-der.?
4. Ancient Greekθέειον (théeion)
5. Ancient Greekθεῖον (theîon)
6. Englishthio-
7. Proto-Indo-European*né
8. Proto-Indo-European*n̥-
9. Proto-Hellenic*ə-
10. Ancient Greekᾰ̓- (ă-)
11. Proto-Indo-European*gʷeyh₃-
12. Proto-Indo-European*gʷih₃wós
13. Proto-Indo-European*gʷíh₃weti
14. Proto-Hellenic*gʷyṓw-ō
15. Proto-Hellenic*d͏̌ṓwō
16. Ancient Greekζώω (zṓō)
17. Ancient Greekζῶ (zô)
18. Ancient Greekζωή (zōḗ)
19. Frenchazote
20. Englishazote
21. Englishazo-
22. Englishazole
23. Englishthiazole
24. English todayisothiazole

From iso- + thiazole.