Blackfriar \Black"fri`ar\, Black friar \Black" fri`ar\(bl[a^]k"fr[imac]`[~e]r). (Eccl.) A friar of the Dominican order, so named because wearing the black mantle of the Dominicans; -- called also {predicant} and {preaching friar}; in France, {Jacobin}. Also, sometimes, a Benedictine. Syn: Dominican. [1913 Webster]