petrochemical

The story

1. Ancient Greekπέτρᾱ (pétrā)
2. Latinpetra
3. Englishpetro-
4. Proto-Indo-European*ǵʰew-
5. Ancient Greekχῠ́μᾰ (khŭ́mă)
6. Ancient Greekχυμείᾱ (khumeíā)
7. Arabicالْكِيمِيَاء (al-kīmiyāʔ)
8. Medieval Latinalchēmia
9. Ancient Greekχυμείᾱ (khumeíā)influ.
10. New Latinchēmia
11. New Latinchēmicus
12. Proto-Indo-European*h₂el-
13. Proto-Indo-European*h₂élisder.?
14. Englishchemical
15. English todaypetrochemical

From petro- + chemical.