photoacoustics

Etymology tree
Proto-Indo-European *bʰeh₂-
Proto-Indo-European *bʰéh₂os
Proto-Hellenic *pʰáwos
Ancient Greek φᾰ́ος (phắos)
Ancient Greek φῶς (phôs)
Ancient Greek φωτο- (phōto-)der.
English photo-
Proto-Indo-European *h₂eḱ-
Proto-Indo-European *h₂ew-
Proto-Indo-European *-s
Proto-Indo-European *h₂ṓws
Proto-Indo-European *-yéti
Proto-Indo-European *h₂ḱh₂owsyéti
Proto-Hellenic *akóuhō
Ancient Greek ἀκούω (akoúō)
Proto-Indo-European *-kos
Ancient Greek -κός (-kós)
Ancient Greek -ῐκός (-ĭkós)
Ancient Greek ᾰ̓κουστῐκός (ăkoustĭkós)bor.
Medieval Latin acousticusbor.
English acoustic
Old English -as
Middle English -es
English -s
English acoustics
English photoacoustics
From photo- + acoustics.