hydroxysteroid

The story

1. Proto-Indo-European*wed-
2. Proto-Indo-European*wódr̥
3. Proto-Hellenic*údōr
4. Ancient Greekῡ̆̔́δωρ (hū̆́dōr)
5. Ancient Greekὑδρο- (hudro-)
6. Frenchhydro-
7. Proto-Indo-European*ǵenh₁-
8. Proto-Indo-European*ǵénh₁os
9. Proto-Hellenic*génos
10. Ancient Greekγένος (génos)
11. Frenchhydrogène
12. Englishhydrogen
13. Proto-Indo-European*h₂eḱ-der.?
14. Ancient Greekὀξύς (oxús)
15. Ancient Greekγένος (génos)
16. Frenchoxygène
17. Englishoxygen
18. Proto-Indo-European*swel-der.?
19. Ancient Greekῡ̔́λη (hū́lē)
20. Englishhydroxyl
21. Englishhydroxy-
22. Proto-Indo-European*ǵʰelh₃-
23. Proto-Hellenic*kʰolā́
24. Ancient Greekχολή (kholḗ)
25. Proto-Indo-European*ster-
26. Ancient Greekστερεός (stereós)
27. Frenchcholestérine
28. Frenchcholestéro
29. Englishcholesterol
30. Englishsterol
31. Proto-Indo-European*weyd-
32. Proto-Indo-European*wéydos
33. Proto-Hellenic*wéidos
34. Ancient Greekεἶδος (eîdos)
35. Englishsteroid
36. English todayhydroxysteroid

From hydroxy- + steroid.