autocoherent

The story

1. Proto-Indo-European*h₂ew
2. Proto-Indo-European*tó-
3. Proto-Hellenic*autós
4. Proto-Indo-European*h₂ew
5. Ancient Greekαὖ (aû)
6. Ancient Greekτόν (tón)
7. Ancient Greekαὐτός (autós)
8. Ancient Greekαὐτο- (auto-)
9. Englishauto-
10. Proto-Indo-European*ḱe?
11. Proto-Indo-European*ḱóm
12. Proto-Italic*kom
13. Proto-Italic*kom-
14. Latincon-
15. Latinhaereō
16. Latincohaereō
17. Latincohaerēns
18. Middle Frenchcoherent
19. Englishcoherent
20. English todayautocoherent

From auto- + coherent.