• 血液けつえき — blood (as fluid)
• 出血しゅっけつ — bleeding
• 輸血ゆけつ — blood transfusion
• 熱血ねっけつ — hot-blooded / passionate
• 献血けんけつ — blood donation
• 純血じゅんけつ — pure blood
• 流血りゅうけつ — bloodshed
• 冷血れいけつ — cold-blooded

血 is a pictographic character that resembles drops of blood in a vessel. It symbolizes life force and connection to kinship or passion in metaphorical use. It’s widely used in medical and emotional contexts.