硬こう石せっけん

noun

hard soap; soda soap

Soap made with sodium hydroxide, producing a solid bar; contrasted with ソーダ石鹸 (soda soap) in some contexts, though often used synonymously.

See also: ソーダ石鹸

• 硬こう石せっけんは洗せん濯たく用ようとしてよく使つかわれる。

  Hard soap is often used for laundry.

• この硬こう石