The word 'audible' often relates to volume, meaning the sound is loud enough to hear. The whispers were audible despite the crowd noise.
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Hearing Range
'Audible' indicates a sound falls within the hearing range of humans, not too high or low. The dog's bark was audible, but the ultrasonic whistle wasn't.
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Literal Use
When 'audible' describes a noise or sound, it is a literal, physical phenomenon. The sound of the bell was clearly audible across the field.