hydrocyanic acid; prussic acid; hydrogen cyanide
Chemistry term for the aqueous solution of hydrogen cyanide; synonymous with 青酸 (seisan).
See also: 青酸
Hydrocyanic acid is highly toxic, so careful handling is required.
青酸 is a common abbreviation for シアン化水素酸, used in compounds like 青酸カリ (potassium cyanide).
シアン化水素 refers specifically to hydrogen cyanide gas, while シアン化水素酸 is its aqueous solution.
Compound of シアン化 (cyanide) + 水素 (hydrogen) + 酸 (acid), calqued from English 'hydrocyanic acid'.