martial pert. to war or battle XIV; pert. to the army, military (court martial, martial law); warlike XV; of the planet Mars XVII. — (O)F. martial or L. mārtiālis, f. Mārs (for Māvors), Mārti-, Roman god of war, planet fourth in order of distance from the sun; see -IAL.
So Martian pert. to the planet Mars XIV; to the month of March XVII. — OF. martien or L. Mārtiānus.

mar·tial / ˈmärshəl/ • adj. of or appropriate to war; warlike: martial bravery.DERIVATIVES: mar·tial·ly adv.