cyclooctatetraene

The story

1. Late Latincyclus
2. Middle Englishcicle
3. Englishcycle
4. Ancient Greekκυκλῐκός (kuklĭkós)
5. Classical Latincyclicu
6. Middle Frenchcyclique
7. Frenchcyclique
8. Classical Latincyclicus
9. Englishcyclic
10. Englishcyclo-
11. Proto-Indo-European*oḱtṓw
12. Proto-Hellenic*oktṓ
13. Ancient Greekὀκτώ (oktṓ)
14. Ancient Greekὀκτᾰ- (oktă-)
15. Englishocta-
16. Proto-Indo-European*kʷetwóres
17. Proto-Hellenic*kʷétwores
18. Ancient Greekτέσσᾰρες (téssăres)
19. Ancient Greekτετρᾰ- (tetră-)
20. Englishtetra-
21. English todaycyclooctatetraene

From cyclo- + octa- + tetra- + -ene.