In Australia we say "ground" spice. It appears the French say ground also:
I could find no reference to "powdered" spices.
Actually, en poudre is the most common generalisation for ready ground spices in French. There is a subtle distinction between something you grind up yourself and commercial ground spices, en poudre is refering to the state of the finished product. So, if you are preparing your own spices, milled (bought or if you have the luxury of a little electric grinder) is moulu, pounded (i.e. with a pestle and mortar) is pilé and crushed is écrasé.(These are all masculine singular forms.) Hope this helps.