Marsian adjective 1noun 1forms 1 adjective1 •Of or relating to the Marsi.Caso Cantovios Aprufclanos [set up] pillars at the Esalican boundary in the city Casontonia; and his allies brought a sacred gift to Angitia on behalf of Marsian legions. — 1940 noun1 •Any member of the Marsi. formsMarsians