quadroxide

The story

1. Proto-Indo-European*kʷetwóres
2. Proto-Indo-European*kʷetwr̥-
3. Proto-Italic*kʷetru-
4. Latinquadri-
5. Englishquadri-
6. Proto-Indo-European*h₂eḱ-der.?
7. Ancient Greekὀξύς (oxús)
8. Proto-Indo-European*ǵenh₁-
9. Proto-Indo-European*ǵénh₁os
10. Proto-Hellenic*génos
11. Ancient Greekγένος (génos)
12. Frenchoxygène
13. Latinacidu
14. Frenchacide
15. Frenchoxide
16. Englishoxide
17. English todayquadroxide

From quadri- + oxide.