acoustic

1 ENTRIES FOUND:
acoustic /əˈkuːstɪk/ adjective
also US acoustical /əˈkuːstɪkəl/
acoustic
/əˈkuːstɪk/
adjective
also US acoustical /əˈkuːstɪkəl/
Britannica Dictionary definition of ACOUSTIC
1 
: of or relating to sound or to the sense of hearing
2 
a  of a musical instrument : not having its sound changed by electrical devices
b  : made with or using acoustic instruments

— acoustically

/əˈkuːstɪkli/ adverb