phosphodiester

The story

1. Proto-Indo-European*bʰeh₂-
2. Proto-Indo-European*bʰéh₂os
3. Proto-Hellenic*pʰáwos
4. Ancient Greekφᾰ́ος (phắos)
5. Ancient Greekφῶς (phôs)
6. Proto-Indo-European*bʰer-
7. Proto-Indo-European*bʰéreti
8. Proto-Hellenic*pʰérō
9. Ancient Greekφέρω (phérō)
10. Ancient Greekφωσφόρος (phōsphóros)
11. Latinphōsphorus
12. Englishphosphorus
13. Englishphospho-
14. Proto-Indo-European*dwóh₁
15. Proto-Indo-European*dwi-
16. Proto-Hellenic*dwi-
17. Ancient Greekδῐ- (dĭ-)
18. Latindi-
19. Englishdi-
20. Proto-Indo-European*h₂eḱ-
21. Proto-Indo-European*h₂eḱéh₁yeti
22. Proto-Italic*akēō
23. Latinaceō
24. Latinacēscō
25. Latinacētum
26. Proto-West Germanic*aket
27. Proto-West Germanic*atek
28. Old High Germaneȥȥih
29. Middle High Germaneȥȥich
30. GermanEssich
31. GermanEssig
32. Proto-Indo-European*h₂eydʰ-
33. Proto-Hellenic*áitʰō
34. Ancient Greekαἴθω (aíthō)
35. Ancient Greekᾱ̓ήρ (āḗr)influ.?
36. Ancient Greekαἰθήρ (aithḗr)
37. Latinaethēr
38. GermanÄther
39. GermanEster
40. Englishester
41. Englishdiester
42. English todayphosphodiester

From phospho- + diester.