त्रयी

rayividyA> tevijja should be correctly understood both in the pALi & early Skt contexts as the 3 types of mantra-s: R^ik-s, sAman-s, yajuSh-es.

• The RV saMhitA is only 1st type;
• the SV saMhitA is 2nd; SV brAhmaNa-s have all 3 types; e.g., pa~nchaviMsha-brAhmaNa opens with the yajuSh-es of the taNDin-s.
• The YV saMhitA-s have both R^ik-s& yajuSh-es. The YV-s have parishiShTha-s with RV style R^ik collections for hautra roles.
• AV is a collection of RV-style R^ik-s; yajuSh-es & a special class of incantation most commonly of the bheShaja type. These types have clear Iranic cognates – yasna haptangaiti is Iranic yajuSh.

Thus, the 3 types of mantra-s – the trayi – likely had a deep presence in the Aryan tradition & was only partially aligned to the saMhitA collections.