mixture of spices
used to make, well, chili
Store-bought chili powder contains ground chili peppers, cumin, oregano, garlic and salt. It can be either mild or hot.
I have made my own chili powder from dried chilies and the other spices ground in a spice mill. Mmmm.
If you're serious about your chili, you probably won't use chili powder and will get real chilies whether dried or fresh if you're lucky enough to live somewhere where they're readily available. If you don't, or you're just used to cooking with it, a good chili powder is a reasonable compromise especially if you put other peppers in your chili, like bell peppers
or Anaheim peppers or something tasty like that.