The joint family in this Marumakkatayam system is called a Tarwad. It is a juristic entity representing the group. It consists of females and their female descendants since woman is the stock of descent in the matriarchal system. A deceased female member is represented by her sons.
Just as there is a coparcenary within a coparcenary in the Mitakshara joint family, a tarwad may be composed to tavazhis or branches. A Tavazhi is part of a Tarwad and it consists of a female, her children and descendants in the female line. A tavazhi may have separate property of its own.
The significant feature of the Tarwad is that its female members continue in the same tarwad even after marriage. The property is managed by the senior most male member called the karnavan. The property of the Tarwad was inalienable except by the Karnavan who had limited power to alienate it for necessity.
The Kutumba and Kavaru of the Aliyasantana family correspond to the Tarwad and Tavazhi of Marummakkatayam family. The Aliyasantana system differs from the Marumakkatayam in a few aspects. The tarwad may be managed in this system by the eldest member (even if such member be a female). This system was not applicable to Brahmins.
The illom corresponds to Tarwad and is the expression in use amongst Nambudris (Brahmins of Kerala).