Vaisesika Sūtra 5.2.25

गुणैर्दिग्व्याख्याता ॥२५॥

guṇair dig vyākhyātā ॥25॥

[गुणैः (guṇaiḥ) - by qualities; दिक् (dik) - direction; व्याख्याता (vyākhyātā) - has been explained;]

Direction has been explained through the qualities.