pertaining to a master; magisterial; authoritative; dogmatic.-commanded or prescribed by a magister, esp. by a doctor; hence, effectual; sovereign; as, a magistral sirup.-formulated extemporaneously, or for a special case; -- opposed to officinal, and said of prescriptions and medicines.-a sovereign medicine or remedy.-a magistral line.-powdered copper pyrites used in the amalgamation of ores of silver, as at the spanish mines of mexico and south america.