洗せん濯たく粉こ

noun

laundry detergent powder

Refers specifically to powdered detergent used for washing clothes. Less common in modern usage where liquid detergents are prevalent, but still understood.

• 洗せん濯たく粉こを入いれて洗せん濯たく機きを回まわす。

  I put in laundry detergent powder and run the washing machine.