soma, n. — Green’s Dictionary of Slang

soma n.

[Skrt soma, a drug used in Vedic rituals. Note Soma, Aldous Huxley’s name for the ‘happiness’ drug used in his novel Brave New World (1932) + SOMA, the Society of Mental Awareness, formed in 1967 to campaign for the legalization of cannabis in the UK]

(drugs) phencyclidine.

1979		H. Feldman et al. Angel Dust 124: The large number of street names it has been accorded over the years: [...] soma.
2001		ONDCP Street Terms 20: Soma — PCP.