This is the 3853rd most frequent French word.
acoustique
"Acoustique" in English means "related to sound or hearing."
Here 'acoustique' refers to the quality of sound in an environment, specifically how sound is perceived; it is used as a noun.
La salle a une excellente acoustique pour les concerts.
The hall has excellent acoustics for concerts.
In this sentence, 'acoustique' acts as an adjective qualifying 'properties,' relating to sound characteristics.
Le scientifique étudie les propriétés acoustiques des matériaux.
The scientist is studying the acoustic properties of materials.
Here 'acoustique' describes the type of guitar based on how it produces sound; it is used as an adjective.