Although svaha is not a seed-syllable term because it has two syllables, in Buddhist mantras, it functions in the same way as a seed syllable mantra would. Svaha first appears in the Buddhist texts of the Dharanis, which were incorporated into the Mahayana Buddhist sutras, such as the "White Lotus" and the "Golden Light."
In the "Rig Veda," svaha is used as a feminine noun which may mean an offering to Agni, the fire god. Some say that Svaha is name of the wife of Agni and of a minor goddess who was previously a nymph. Svaha is chanted during havissu, an offering made during yagnas, which is a ritual made in front of a sacred fire. This may be another explanation for its use at the end of mantras because it is a way of offering the mantra up to the gods, similar to a fire offering.