cyclohexane

The story

1. Proto-Indo-European*kʷelh₁-redup.
2. Proto-Indo-European*kʷékʷlos
3. Proto-Hellenic*kʷókʷlos
4. Proto-Hellenic*kúklos
5. Ancient Greekκύκλος (kúklos)
6. Late Latincyclus
7. Middle Englishcicle
8. Englishcycle
9. Ancient Greekκύκλος (kúklos)
10. Ancient Greekκυκλῐκός (kuklĭkós)
11. Classical Latincyclicu
12. Middle Frenchcyclique
13. Frenchcyclique
14. Classical Latincyclicus
15. Englishcyclic
16. Englishcyclo-
17. Proto-Indo-European*swéḱs
18. Proto-Hellenic*hwéks
19. Ancient Greekἕξ (héx)
20. Ancient Greekἑξα- (hexa-)
21. Latinhexa-
22. Englishhexa-
23. Englishhex-
24. Englishhexane
25. English todaycyclohexane

From cyclo- + hexane.