When you see a spice jar labeled simply «chili powder,» it's actually a mix of ground chiles with several spices like oregano, garlic powder, and cumin. (finecooking.com)
Curry powder is a mixture of several spices — turmeric, cumin, coriander, to name a few. (filipino-food-recipes.com)
Ancho chile powder is made up purely of dried and ground ancho chiles (as opposed to standard «chili powder,» which is actually a mix of ground chiles with several spices like oregano, garlic powder, and cumin. (finecooking.com)