Prejudice isn't discrimination, it's just prejudice.
Prejudice COULD be discriminatory, but it doesn't have to be.
Racism is racial prejudice.
By adding the "plus power" you're redefining a word to absolve all the people without power, but that's nonsense: everyone has SOME power, even if they don't have all the power. But you have to put power aside, because prejudice (and racial prejudice, which is the definition of racism) exists with or without power.