acousticopalpebral

The story

1. Proto-Indo-European*h₂eḱ-
2. Proto-Indo-European*h₂ew-
3. Proto-Indo-European*h₂ṓws
4. Proto-Indo-European*h₂ḱh₂owsyéti
5. Proto-Hellenic*akóuhō
6. Ancient Greekἀκούω (akoúō)
7. Ancient Greekᾰ̓κουστῐκός (ăkoustĭkós)
8. Medieval Latinacousticus
9. Englishacoustic
10. Latinpalpō
11. Proto-Italic*ðrā
12. Latinpalpebra
13. Proto-Indo-European*h₂el-
14. Proto-Indo-European*h₂élisder.?
15. Late Latinpalpebrālis
16. Englishpalpebral
17. English todayacousticopalpebral

From acoustic + -o- + palpebral.