acetophenone

The story

1. Proto-Indo-European*h₂eḱ-
2. Proto-Indo-European*h₂eḱéh₁yeti
3. Proto-Italic*akēō
4. Latinaceō
5. Latinacēscō
6. Latinacētum
7. Englishaceto-
8. Proto-Indo-European*bʰeh₂-
9. Proto-Indo-European*bʰh₂nyéti
10. Proto-Hellenic*pʰáňňō
11. Ancient Greekφαίνω (phaínō)
12. Frenchphéno-
13. Proto-Indo-European*swel-der.?
14. Ancient Greekῡ̔́λη (hū́lē)
15. Frenchphényle
16. Englishphenyl
17. GermanKeton
18. Englishketone
19. Englishphenone
20. English todayacetophenone

From aceto- + phenone.