산성이 · 산성을
acidity, acidic (nature)
Example
산성비는 숲과 건물에 큰 피해를 줍니다.
Acid rain causes great damage to forests and buildings.
Word parts
산 acid+성 nature
Literally 'acid nature'. -성 = nature, quality: 산성, 가능성.
Good to know
Homonym warning: 산성 (山城) also means 'mountain fortress', as in 남한산성.
Related words