The word vṛtta is formed from the causative of vṛt in the sense of 'studied through or read'.,
There is absence of इट् and luk-elision of the causative sign. As वृत्तो गुणो देवदत्तेन 'Devadatta has read or gone through Guna.' (गुणः पाठः पदक्रमसंहिता रूपोऽध्यनविशेषः)॥ वृत्तं पारायणं देवदत्तेन ॥ When the sense is not that of 'read', we have वर्त्तितम् ॥ The root वृत् is intransitive, and becomes Transitive when employed in the Causative. The participle is formed from this Transitive causative verb, otherwise it could not have governed an object as shown above. \The affix क्त is added with a Passive force to वृत्, as we find the author himself using this form in निर्वृत्तम् in sutras 4.2.68, and (V. I. 79); on the analogy of निर्वृत्त the word वृत्तः could also have been formed without this sutra.\,