Mars brown noun a medium brown color. a brown pigment used in painting, artificially made from an iron oxide base and characterized by strong film-forming properties and permanence. Liberaldictionary.com What It Really Means to Call Someone "Crude" Can You Translate These Famous Phrases From Emoji? These Are the Longest Words in English These Are the Saddest Phrases in English Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019