subcompartmentalization

The story

1. Proto-Indo-European*upó
2. Proto-Italic*supo
3. Latinsub
4. Latinsub-
5. Englishsub-
6. Proto-Indo-European*ḱe?
7. Proto-Indo-European*ḱóm
8. Proto-Italic*kom
9. Proto-Italic*kom-
10. Latincom-
11. Proto-Indo-European*perh₃-
12. Proto-Indo-European*pérh₃tis?
13. Proto-Italic*partis
14. Latinpars
15. Latinpartiō
16. Latinpartior
17. Latincompartīrī
18. Italiancompartire
19. Italiancompartimento
20. Middle Frenchcompartiment
21. Englishcompartment
22. Proto-Indo-European*h₂el-
23. Proto-Indo-European*h₂élisder.?
24. Englishcompartmental
25. Englishcompartmentalize
26. Englishcompartmentalization
27. English todaysubcompartmentalization

From sub- + compartmentalization.