Soma (Sanskrit: soma) or haoma (Avestan) is a Vedic ritual drink of importance among the early Indians. It is mentioned in the Rigveda, particularly in the Soma Mandala. In the Avestan literature, haoma has the entire Yasht 20 and Yasna 9–11 dedicated to it.
It is described as being prepared by extracting the juice from a plant, the identity of which is now unknown and debated among scholars. In both Hinduism and Zoroastrianism, the name of the drink and the plant are the same.
There has been much speculation concerning what is most likely to have been the identity of the original plant. However, traditional accounts with unbroken continuity in Southern India, from Ayurveda and Siddha medicine practitioners and Somayajna ritualists undoubtedly use "Somalata" (Sarcostemma acidum). Non Indian researchers proposed candidates include Amanita muscaria, Psilocybe cubensis, Peganum harmala and Ephedra sinica.
Soma is a Vedic Sanskrit word that literally means "distill, extract, sprinkle", often connected in the context of rituals.
Soma, and its cognate the Avestan haoma, are thought to be derived from Proto-Indo-Iranian *sauma-. The name of the Scythian tribe Hauma-varga is related to the word, and probably connected with the ritual. The word is derived from an Indo-Iranian root *sav- (Sanskrit sav-/su) "to press", i.e. *sau-ma- is the drink prepared by pressing the stalks of a plant. According to Mayrhofer, the root is Proto-Indo-European (*sew(h)-)