uniconceptual

The story

1. Proto-Indo-European*ís?
2. Proto-Indo-European*h₁óynos
3. Proto-Italic*oinos
4. Old Latinoinos
5. Latinūnus
6. Latinūni-
7. Englishuni-
8. Proto-Indo-European*ḱe?
9. Proto-Indo-European*ḱóm
10. Proto-Italic*kom
11. Proto-Italic*kom-
12. Latincon-
13. Proto-Indo-European*kap-
14. Proto-Indo-European*kapyéti
15. Proto-Italic*kapjō
16. Latincapiō
17. Ancient Greekσῠλλᾰμβᾰ́νω (sŭllămbắnō)
18. Latinconcipiō
19. Latinconceptus
20. Proto-Indo-European*h₂el-
21. Proto-Indo-European*h₂élisder.?
22. Medieval Latinconceptuālis
23. Englishconceptual
24. English todayuniconceptual

From uni- + conceptual.