noun, masculine/misˈteɾjo/plural: misterios
misterio is masculine in Spanish.
mystery, mysteriousness; crib, nativity scene; mystery, event in Jesus' life
Synonyms: arcano, belén, nacimiento, pesebre, pasito
Borrowed from Latin mystērium, from Ancient Greek μυστήριον (mustḗrion), from μύστης (mústēs, “one who has been initiated”).