prah

1. powder
   Kupila sam mleko u prahu za put. — I bought powdered milk for the trip.
   Kakao u prahu dodaj na kraju. — Add the cocoa powder at the end.
2. formal dust
   Stari grad je pretvoren u prah. — The old town was reduced to dust.
3. formal (of the dead) ashes; remains
   Njegov prah je prosut u Dunav. — His ashes were scattered in the Danube.

Everyday "dust" is usually prašina and household "powder" is prašak; prah is mostly heard in u prahu.