酸素
さんそ · sanso · JLPT N3 · noun
oxygen
🫁 酸素 = acid (酸) + element (素): the acid-making element
Same logic as the Greek oxy-gen, acid-former: early chemists thought oxygen was what made acids sour. 酸 is the sour/acid character, 素 means element, as in 水素 (hydrogen, water-element) and 炭素 (carbon).
酸 — wine/jar radical 酉 + 夋 (phonetic)
酸 is a semantic-phonetic compound. The left side 酉 depicts a wine jar and signals meanings related to fermentation and alcohol. The right side 夋 supplies the sound. Originally describing the sour taste of fermented wine, it broadened to mean 'sour' in general and figuratively 'aching' or 'sad'.
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.