noun

• (astronomy) The fourth planet in the solar system. Symbol: ♂
• (Roman mythology) The Roman god of war.
• (poetic) War; a personification of war.
• (heraldry, rare) Gules (red), in the postmedieval practice of blazoning the tinctures of certain sovereigns' (especially British monarchs') coats as planets.
• (obsolete, alchemy, chemistry) Iron.
• The Mars Bar, a brand of chocolate bar with caramel and nougat filling.
• Alternative form of Mas [(now historical, chiefly in representations of US and Caribbean dialect) Master, used as a title of respect.]
• Initialism of Military Auxiliary Radio System.
• Acronym of Mid-Atlantic Regional Spaceport.
• Abbreviation of multicast address resolution server.