血圧
けつあつ · ketsuatsu · JLPT N2 · noun
blood pressure
🩸 血 = blood, 圧 = pressure, so 血圧 = blood + pressure = blood pressure
The compound reads ketsu (blood) + atsu (pressure). The same 圧 appears in 気圧 (kiatsu, air pressure), so learn 圧 once and it unlocks both words.
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.