公害
こうがい · kougai · JLPT N2 · noun
pollution
🏭 公 (public) + 害 (harm) = harm to the public, i.e. pollution or nuisance
公 means public or common, and 害 means harm or damage. Together they name harm that spreads across a whole community, such as smoke or waste from factories.
公 — eight 八 + private 厶
Originally an ideograph showing 八 (to divide) over 厶 (private/self), depicting the act of splitting away from selfish interest. The combination came to mean 'public' or 'fair,' the opposite of private. It later extended to senses like 'duke,' 'lord,' and 'grandfather.'
害 — 宀 roof + 丯 (phonetic) + 口 mouth
Originally an ideograph showing harm spoken under a roof, with 宀 (roof/house) on top, a phonetic element 丯 in the middle, and 口 (mouth) below suggesting harmful speech. Over time it shifted from 'injury caused by words' to the broader senses of 'harm,' 'injure,' and 'fear.'