Suparna said This direction, in days of old, was given away by Vivasvat after the performance of a sacrifice according to the usual custom as a final present (Dakshina) to his spiritual guide; so this direction is called south (Dakshina).
सुपर्ण उवाच इयं विवस्वता पूर्वं श्रौतेन विधिना किल। गुरवे दक्षिणां दत्ता दक्षिणेत्युच्यते च दिक्॥