hydroacoustichydroacoustic

Hydroacoustic comes from Ancient Greek ᾰ̓κουστῐκός ‘of or for hearing’, from ἀκούω ‘to hear’, and ultimately from Proto-Indo-European *h₂ew- ‘to enjoy’.

1. Proto-Indo-Europeanc. 4500–2500 BCE*h₂ew-‘to enjoy’reconstructed
2. Proto-Indo-European, derivedc. 4500–2500 BCE*h₂ṓws‘ear’reconstructed
3. Proto-Indo-European, derivedc. 4500–2500 BCE*h₂ḱh₂owsyéti‘to be sharp-eared, to hear well’reconstructed
4. Proto-Hellenicc. 2200–1600 BCE*akóuhō‘to hear’reconstructed
5. Ancient Greekc. 800–300 BCEἀκούωakoúō‘to hear’
6. Ancient Greek, derivedc. 800–300 BCEᾰ̓κουστῐκόςăkoustĭkós‘of or for hearing’
7. Medieval Latinmodernacousticus
8. English1500–presentacoustic
9. Englishtodayhydroacoustic