from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Of or relating to the sense of hearing; aural.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. of, or relating to hearing, or to the sense or organs of hearing
audi(o)- + -al1.(American Heritage® Dictionary of the English Language, Fourth Edition)
Latin audire ("to hear") (Wiktionary)