μυστήριον
Alt. μυστήριον, ου, τό,
Etym. μύστης
1. "a mystery or secret doctrine;" in pl., τὰ μ. "the mysteries" of the Cabiri in Samothrace, Hdt.; of Demeter at Eleusis, Aesch., etc.
2. "any mystery or secret", Plat.
3. "mystic implements", Eur., Ar.
4. in NTest. "a mystery, a divine secret, something above human intelligence."