nabho-guna-viseso ’rtho

 yasya tac chrotram ucyate

vayor guna-viseso ’rtho

 yasya tat sparsanam viduh

 

Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 

 

The sense whose object of perception is sound is called the auditory sense, and that whose object of perception is touch is called the tactile sense.

 

Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 

 

Sound is one of the qualifications of the sky and is the subject matter for hearing. Similarly, touch is the qualification of the air and is the subject of the touch sensation.