postmeridian

The story

1. Proto-Indo-European*pós
2. Proto-Indo-European*pósti
3. Proto-Italic*posti
4. Old Latinposte
5. Latinpost
6. Englishpost-
7. Proto-Indo-European*me
8. Proto-Indo-European*dʰeh₁-?
9. Proto-Indo-European*médʰi
10. Proto-Indo-European*médʰyos
11. Proto-Italic*meðios
12. Latinmedius
13. Proto-Indo-European*dyew-
14. Proto-Indo-European*dyḗws
15. Proto-Italic*djous
16. Latindiēs
17. Latinmedīdiēs
18. Latinmerīdiēs
19. Latinmerīdiānus
20. Middle Englishmeridian
21. Englishmeridian
22. English todaypostmeridian

From post- + meridian.