Definition of powder:
a solid substance in the form of tiny loose particles; a solid that has been pulverized
a mixture of potassium nitrate, charcoal, and sulfur in a 75:15:10 ratio which is used in gunnery, time fuses, and fireworks
any of various cosmetic or medical preparations dispensed in the form of a pulverized powder
make into a powder by breaking up or cause to become dust; "pulverize the grains"
apply powder to; "She powdered her nose"; "The King wears a powdered wig"