A medical condition of dullness or reduced sensitivity to sound; partial hearing loss or diminished auditory perception.
From Greek amblys 'dull, blunt, obtuse' + akouein 'to hear' + -ia (medical condition suffix). This medical term literally describes 'blunt hearing' or dulled auditory sensation.
The prefix 'ambly-' means blunt or dull in Greek, so it appears in lots of medical terms for things that don't work quite right—amblyopia (lazy eye), amblyacousia (dull hearing)—it's a category of 'blunt' problems.
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