Both Uses

audible
in
The Monkey's Paw
(Auto-generated)

There was no reply; the old woman's face was white, her eyes staring, and her breath inaudible; on the husband's face was a look such as his friend the sergeant might have carried into his first action.†
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inaudible = not capable of being heard

standard prefix: The prefix "in-" in inaudible means not and reverses the meaning of audible. This is the same pattern you see in words like invisible, incomplete, and insecure.
At the foot of the stairs the match went out, and he paused to strike another; and at the same moment a knock, so quiet and stealthy as to be scarcely audible, sounded on the front door.†

audible = capable of being heard

Definitions:

(1) (audible as in: barely audible)
capable of being heard
(2) (meaning too rare to warrant focus)
In football, the term has come to include an instruction shouted from the line of scrimmage.

Recently, the word is also being used to indicate sounds that could be played on a phone or computer; for example "audibles include creative hellos that can be downloaded."