dibutyl

The story

1. Proto-Indo-European*dwóh₁
2. Proto-Indo-European*dwi-
3. Proto-Hellenic*dwi-
4. Ancient Greekδῐ- (dĭ-)
5. Latindi-
6. Englishdi-
7. Proto-Indo-European*gʷṓws
8. Proto-Hellenic*gʷous
9. Ancient Greekβοῦς (boûs)
10. Proto-Indo-European*tewh₂-
11. Proto-Indo-European*tuh₂rós
12. Proto-Hellenic*tūrós
13. Ancient Greekτῡρός (tūrós)
14. Ancient Greekβούτῡρος (boútūros)
15. Englishbut-
16. Proto-Indo-European*swel-der.?
17. Ancient Greekῡ̔́λη (hū́lē)
18. Englishbutyl
19. English todaydibutyl

From di- + butyl.