fenbenicillin

The story

1. Proto-Indo-European*bʰeh₂-
2. Proto-Indo-European*bʰh₂nyéti
3. Proto-Hellenic*pʰáňňō
4. Ancient Greekφαίνω (phaínō)
5. Frenchphéno-
6. Proto-Indo-European*swel-der.?
7. Ancient Greekῡ̔́λη (hū́lē)
8. Frenchphényle
9. Englishphenyl
10. Englishpheno-
11. Englishphen-
12. Arabicلُبَان (lubān)
13. Proto-Indo-European*yew-
14. Proto-Indo-European*yéwos
15. Proto-Indo-Iranian*yáwas
16. Sanskritयव (yava)bor.?
17. Proto-Austronesian*zawa
18. Proto-Malayo-Polynesian*zawader.?
19. Old Javanesejawa
20. Old JavaneseJawi
21. Javaneseꦗꦮꦶ (jawi)
22. Arabicجَاوَة (jāwa)
23. Arabicـِيّ (-iyy)
24. Arabicجَاوِيّ (jāwiyy)
25. Arabicلُبَان جَاوِيّ (lubān jāwiyy)
26. Catalanbenjuí
27. Middle Frenchbenjoin
28. Englishbenzoin
29. Englishbenzo-
30. Englishbenz-
31. Ancient Greekῡ̔́λη (hū́lē)
32. Englishbenzyl
33. Proto-Indo-European*pes-
34. Proto-Indo-European*pes-ni-s
35. Proto-Italic*peznis
36. Latinpēnis
37. Latinpēniculus
38. Latinpēnicillum
39. Englishpenicillin
40. English todayfenbenicillin

From phen- + ben(zyl) + (pen)icillin.