esterification

The story

1. Proto-Indo-European*h₂eḱ-
2. Proto-Indo-European*h₂eḱéh₁yeti
3. Proto-Italic*akēō
4. Latinaceō
5. Latinacēscō
6. Latinacētum
7. Proto-West Germanic*aket
8. Proto-West Germanic*atek
9. Old High Germaneȥȥih
10. Middle High Germaneȥȥich
11. GermanEssich
12. GermanEssig
13. Proto-Indo-European*h₂eydʰ-
14. Proto-Hellenic*áitʰō
15. Ancient Greekαἴθω (aíthō)
16. Ancient Greekᾱ̓ήρ (āḗr)influ.?
17. Ancient Greekαἰθήρ (aithḗr)
18. Latinaethēr
19. GermanÄther
20. GermanEster
21. Englishester
22. English todayesterification

From ester + -ification.