cochairwoman

The story

1. Proto-Indo-European*ḱe?
2. Proto-Indo-European*ḱóm
3. Proto-Italic*kom
4. Proto-Italic*kom-
5. Latincon-
6. Latinco-
7. Englishco-
8. Proto-Indo-European*ḱóm
9. Proto-Indo-European*ḱm̥-th₂der.?
10. Proto-Hellenic*kətá
11. Ancient Greekκατά (katá)
12. Proto-Indo-European*sed-
13. Proto-Indo-European*sedreh₂
14. Proto-Hellenic*hédrā
15. Ancient Greekἕδρα (hédra)
16. Ancient Greekκᾰθέδρᾱ (kăthédrā)
17. Latincathedra
18. Old Frenchchaiere
19. Middle Englishchayere
20. Englishchair
21. Proto-Germanic*wībą
22. Proto-West Germanic*wīb
23. Old Englishwīf
24. Proto-Indo-European*mon-
25. Proto-Germanic*mann-
26. Proto-West Germanic*mann
27. Old Englishmann
28. Old Englishwīfmann
29. Middle Englishwoman
30. Englishchairwoman
31. English todaycochairwoman

From co- + chairwoman.