輸血
ゆけつ · yuketsu · JLPT N2 · noun
transfusion
🩸💉 輸 = transport, 血 = blood: transport blood into a patient's body
輸 (yu) means carry or send across, as in 輸入 (import). 血 (ketsu) means blood, as in 血液. Together they describe blood carried into the body.
血 — drop 丿 over dish 皿
Originally a pictograph of a sacrificial vessel (皿) with a drop of blood inside, marking the offering of blood in ancient rituals. The small stroke on top represents the blood itself. Over time it broadened from ritual blood to blood in general.