Wordnet 3.0
ADJECTIVE (1)
1. 
 relating to or having or hearing with two ears; 
- Example: "binaural hearing"[syn: binaural, biaural]
WordNet (r) 3.0 (2006):
biaural
    adj 1: relating to or having or hearing with two ears; "binaural
           hearing" [syn: binaural, biaural] [ant: monaural]