Princeton's WordNet

1. acoustic(adj)

   a remedy for hearing loss or deafness

2. acoustic, acoustical(adj)

   of or relating to the science of acoustics

   "acoustic properties of a hall"

Wiktionary

1. acoustic(Noun)

   A medicine or other agent to assist hearing.

2. acoustic(Adjective)

   Pertaining to the sense of hearing, the organs of hearing, or the science of sounds; auditory.

3. acoustic(Adjective)

   Naturally producing or produced by an instrument without electrical amplification, as an acoustic guitar or acoustic piano.

Origin: acoustique, from ἀκουστικός.

Webster Dictionary

1. Acoustic(adj)

   pertaining to the sense of hearing, the organs of hearing, or the science of sounds; auditory

2. Acoustic(noun)

   a medicine or agent to assist hearing

Freebase

1. Acoustic

   Acoustic is a compilation album of John Lennon demos, studio and live performances that feature his acoustic guitar work and was released in 2004. Its release was criticised by critics and fans, as nine of the sixteen recordings had previously been released on the 1998 John Lennon Anthology box set, while the remaining inclusions had been bootlegged for years. Although it failed to chart in the United Kingdom, Acoustic reached #31 in the United States, becoming John Lennon's best charting posthumous US release since 1988's Imagine: John Lennon soundtrack. The album debuted on the Billboard 200 album chart on 20 November 2004 at number 31, with sales of 27,858 copies. It spent eight weeks on the chart. This album has been released with the Copy Control protection system in some regions.

• akoestiesAfrikaans
• صَوْتِي، سَمَعِيArabic
• акустиченBulgarian
• acústicoPortuguese (BR)
• akustickýCzech
• akustischGerman
• akustiskDanish
• ακουστικόςGreek
• acústicoSpanish
• akustilineEstonian
• شنوایی؛ صوتیFarsi
• akustinenFinnish
• acoustiqueFrench
• אֲקוּסטִיHebrew
• ध्वनि संबंधीHindi
• zvučniCroatian
• akusztikaiHungarian
• akustikIndonesian
• heyrnar-, hljómburðar-Icelandic
• acusticoItalian
• 聴覚の, 音のJapanese
• 음향의Korean
• akustinisLithuanian
• akustisksLatvian
• akustikMalay
• akoestischDutch
• akustisk, lyd-Norwegian
• akustyczny, dźwiękowyPolish
• شنوایی؛ صوتیPersian
• اوريدونكيPashto
• acústicoPortuguese
• acusticRomanian
• акустическийRussian
• akustický, sluchovýSlovak
• akustičenSlovenian
• akustičkiSerbian
• akustiskSwedish
• ซึ่งเกี่ยวข้องกับเสียงThai
• akustik, işitsel, işitmeye aitTurkish
• 與聽覺或聲音有關的Chinese (Trad.)
• акустичний, звуковийUkrainian
• سمعی ، سننے سے متعلقUrdu
• thuộc âm thanhVietnamese
• 听觉的，声音的Chinese (Simp.)