of, relating to, affecting, or designed for use with two ears
In 1839, German experimenter Heinrich Wilhelm Dove discovered that illusory "beats" are perceived when pure tones of slightly different frequency are separately and simultaneously presented to each ear. Dove's insight was to realize that since there is no acoustic mixing of the tones, the perceived beats must exist solely within the auditory system, specifically that part which processes binaural (e.g., "stereo") sound.
