酸性
さんせい · sansei · JLPT N3 · noun
sourness
🍋 酸性 = sour (酸) + nature (性): having a sour nature = acidity
酸 (san) means sour or acid, as in 酸素 (oxygen, once thought to be the acid-maker). 性 (sei) is the suffix for nature or property, like English -ity. Sound hook: san-sei, the sour-say, what a lemon would say about itself.
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'.
性 — heart radical 忄 + 生 (life/birth)
性 is a semantic-phonetic compound. The heart radical 忄 supplies the meaning, pointing to inner feelings or innate qualities, while 生 ('birth, life') gives the sound and hints at what one is born with. It originally meant 'inborn nature' and later extended to 'character,' 'gender,' and 'sex.'