Natyashastra
विदूषकः सूत्रधारस्तथा वै पारिपार्श्वकः । यत्र कुर्वन्ति सञ्जल्पं तच्चापि त्रिगतं मतम् ॥ २८॥
The Vidūṣaka, Sūtradhāra, and Pāripārśvika are involved in the dialogue or conversation (Sañjalpa), and this conversation is considered a part of the three-fold process (Tri-gata).
english translation
vidUSakaH sUtradhArastathA vai pAripArzvakaH । yatra kurvanti saJjalpaM taccApi trigataM matam ॥ 28॥
hk transliteration by Sanscript