The kanji 酸 primarily conveys the idea of "acid" or "sourness." It refers to substances with a characteristic tart taste and corrosive properties, or the sensation or characteristic of being acidic. It is often associated with chemical compounds that release hydrogen ions (H+) in solution.

・On-yomi (音読み): サン ・Kun-yomi (訓読み): す(っぱい)

⚫︎ 酸性雨 (さんせいう) Translation: Acid rain ⚫︎ 酸っぱい (すっぱい) Translation: Sour ⚫︎ 硫酸 (りゅうさん) Translation: Sulfuric acid

The kanji 酸 is a phono-semantic compound (形声文字, けいせいもじ). The semantic component is 酉 (とり), which originally depicted a wine vessel and, by extension, fermentation or anything related to alcoholic beverages and brewing. The phonetic component is 夋 (すん) which contributes to the sound. Thus, the original meaning of 酸 related to sourness in fermented drinks, but it eventually expanded to encompass the broader concept of acidity.