Blood most often describes the fluid that circulates through your body — the red stuff that seeps out of your finger if you get a paper cut.
Blood can also refer to temperament. If something gets your blood up, that means it makes you angry. You might even get so mad that it feels like your blood boils. You can also use blood to describe a common ancestry. You might have Scottish blood in you — that means some of your ancestors came from Scotland. Blood can also describe family members — you may get frustrated at your brother sometimes but he’s your own flesh and blood.