激素
jī sù · HSK 7
hormone
🧪 激 (stimulate) + 素 (element) = a stimulating element your body releases = hormone
激 means to stir up or stimulate; 素 means a basic element or essence. A hormone is the body's stimulating substance that triggers reactions, so stimulate + element lands right on the meaning.
素 — silk 糸 + sheng 𠂹 (hanging threads)
Originally depicted raw, undyed silk hanging to dry, with the silk radical 糸 below and strands above. From this came the meaning 'plain, unadorned, white,' then extended to 'basic element' or 'plain/simple' in general. The 'vegetarian' sense developed later from the idea of plain, unembellished food.