Sabhasad is the term used to define a person qualified to sit and participate in a sabha (assembly) in ancient India.
Bibliography
Hindu Polity : A Constitutional History of Indian Hindu Times (2005) K P Jayasawal - Chaukhamba Sanskrit Series Varanasi
Encyclopedia of Hinduism Volume IX page 9
In course of time, sabha came to assume the form of the king’s assembly, and its permanent members were called Sabhasads.
Some of them were appointed ministers with different portfolios, and some others held important offices. In a way, they were representatives of the people.
There was one representative for each category or area. Sabhas were held to take important decisions, to receive ambassadors and state guests, and to perform and celebrate important occasions. Naturally, sometimes non-members were also invited.
In the Mahabharata, the main incident which occurred in the sabha of King Dhritarashtra is the disrobing of Draupadi in the presence of all sabhasads, including great warriors such as Bhishma, Dronacharya, Vidura (chief minister), Kauravas and Pandavas.
Dasharatha in Ramayana called all sabhasads for a meeting to crown Sri Rama.
Ravana called the assembly to discuss the strategy for waging war against Rama.
The members of the assembly were appointed, nominated or elected by the king. The assembly took place regularly for taking important decisions and to hold meetings. The assembled maintained decorum and were admonished for transgressing it. All members used to be present well in advance before the king, who would enter last to conduct the proceedings. Important committees were sometimes headed by members of the assembly nominated by the king for taking collective decisions.
Bibliography
Hindu Polity : A Constitutional History of Indian Hindu Times (2005) K P Jayasawal - Chaukhamba Sanskrit Series Varanasi
Encyclopedia of Hinduism Volume IX page 9