Meaning

noun red color or pigment; the chromatic color resembling the hue of blood

noun a tributary of the Mississippi River that flows eastward from Texas along the southern boundary of Oklahoma and through Louisiana

noun emotionally charged terms used to refer to extreme radicals or revolutionaries

originIn reference to the ancient Roman and medieval Byzantine racing faction, a calque of Latin russātī (“Reddish-Brown-Clads”) or factio russata (“the reddish-brown-clad faction”) and Byzantine Greek Ῥούσιοι (Rhoúsioi, “Reds”).

Etymology from Wiktionary, CC BY-SA 3.0