The story
- Proto-Indo-European*bʰeh₂-
- Proto-Indo-European*bʰéh₂os
- Proto-Hellenic*pʰáwos
- Ancient Greekφᾰ́ος (phắos)
- Ancient Greekφῶς (phôs)
- Ancient Greekφωτο- (phōto-)
- Englishphoto-
- Proto-Indo-European*h₂eḱ-
- Proto-Indo-European*h₂ew-
- Proto-Indo-European*h₂ṓws
- Proto-Indo-European*h₂ḱh₂owsyéti
- Proto-Hellenic*akóuhō
- Ancient Greekἀκούω (akoúō)
- Ancient Greekᾰ̓κουστῐκός (ăkoustĭkós)
- Medieval Latinacousticus
- Englishacoustic
- Englishphotoacoustic
- Proto-Indo-European*h₂el-
- Proto-Indo-European*h₂élisder.?
- Proto-Indo-European*leyg-
- Proto-Germanic*līką
- English todayphotoacoustically
From photoacoustic + -ally.
Etymology from Wiktionary, CC BY-SA 4.0.