sangui-

Blood.

Latin sanguis, sanguin‑, blood.

Terms here are often poetic or figurative; literal references to blood, as in medicine, are usually marked by haemo‑. Someone or something sanguinary is bloodthirsty or accompanied by bloodshed; an organ that is sanguineous contains blood; a person who is sanguine is cheerfully optimistic (a term taken from one of the medieval humours, which indicated a constitution associated with the predominance of blood); in heraldry, the word can also refer to a blood-red colour; sanguinaria is a plant, known in North America as bloodroot from the red dye that can be extracted from its rhizomes.