I suspect the definition they were using is power + (white) priviledge = racism. By that definition, racism is the systemic oppression of members of other races by members of a culturally dominant one. IMO, there are some problems with the definition, if nothing else in that the definition has no room for racism between different minority groups, but it's the definition that's preferred, and it does bring a systemic/societal aspect to the table that the normal definition doesn't. It doesn't really deal with prejudice as much as it does with who has the power (intent is actually largely unimportant according to this definition).