One who performs a yajna or sacrifice spending on the material and dakshina is called a "yajamana". "Yaj" (as we seen already) means to worship. The root meaning of "yajamana" is one who performs a sacrifice. In Tamil Nadu nowadays we refer to a "mudalali" as yajaman. It is the mudalali who pays the wages. So it is that we have given him the same place as the yajamana who pays dakshina in sacrifices. That even common folks refer to the mudalali as yajaman shows how deep-rooted the Vedic culture is in the Tamilland.
There is another word which also testifies to the fact that Tamil Nadu is steeped in the Vedic tradition. A place where people are fed free is called a "cattiram" by Tamils. In the North the corresponding word for the sameis "dharamsala"(dharmasala).
How would you explain the use of the word cattiram in the South? It is derived from "sattram" which is the name of a type of Vedic sacrifice. In other sacrifices there is only one yajamana who spends on the material and the dakshina. The priests recieve the dakshina from him and conduct the sacrifice on his behalf. In a sattra all are yajamanas. As we have mentioned earlier any sacrifice brings benefits to all mankind and also serves to cleanse the mind of all those who participate in it - even those who witness the rites are benefitted. But the merit accrues chiefly to the yajamana.
The speciality of a sattra is that all the priests conducting it are yajamanas. It is a kind of socialist yajna in which the merit is equally shared. From this type of sacrifice has originated the term signifying a place or establishment where anyone can come and eat as a matter of right. In a cattiram the one who feeds does not consider himself superior to the one who eats. There is reason to believe that satras had a special place in the tradition of Tamil Nadu.
Among the rtvik Brahmins there are three classes. The "hota"(hotr) chants the rks, the hymns from the Rgveda in praise of the deity, invoking the devata to accept the oblation. Because of the high place accorded to him in a sacrifice we hear even today the remark made with reference to anyone occupying a high position, " hota".
The Rgveda is replete with hymns to various deities. The Yajurveda contains mostly the methods and directions for the conduct of sacrifices. The Brahmin who looks after the conduct of the sacrifice is the "adhvaryu". The "udgata"(udgatr) intones the mantras of the Samaveda to please the deities. There is a Brahmin supervising the sacrifice and he is called the brahma.
The Vedas themselves are called "Brahma". That is why one who learns them (the student) is called a "brahmacharin". The supervisor of the sacrifice, brahma, performs his function in accordance with the Atharvaveda. Thus the hota, the adhvaryu, the udgata and the brahma represent the four Vedas in a sacrifice. In later times, however, the opinion emerged that the brahma is not connected with the Atharvaveda to the same extent as the hota, adhvaryu and udgata are connected respectively with the Rg, Yajur and Sama Vedas. In actual practice also we see that those taking part in sacrifices are conversant with the first three Vedas only and not with the Atharvaveda. For this reason the view is put forward that all sacrifices, from the somayaga to the asvamedha, are to be performed only on the basis of the Rg, Yajur and Sama Vedas.
There are sacrifices which come independently under the Atharvaveda. Acording to Valmiki's Ramayana, Indrajit performed the Nikhumbhila sacrifice mentioned in this Veda. The other three Vedas have a far wider following. Though we customarily speak of the four Vedas (Caturveda), the Rg, Yajur and Saman are bracketed together and specialy spoken of as "Trayi".
(There are three types of sacrifices mentioned in the Atharvaveda: "santikam" for peace; "paustikam" for strength; and " abhicharikam" to bring injury to enemies).
For a general background, please see here