"Aud" comes from the Latin verb "audire," which means "to hear".
Here are some words formed using the "aud" stem:
* audiens (present participle, meaning "hearing" or "listening")
* auditor (noun, meaning "listener" or "auditor")
* audere (verb, meaning "to dare")
* audire (verb, meaning "to hear")
* auditio (noun, meaning "hearing" or "audience")
So, the meaning of "aud" itself depends on the context and the other elements attached to it.