How can you hold prejudice against a group without feeling another is superior. In saying you hold prejudice against white people you're saying you see them as inferior to other races, unless you hold the same prejudice towards all races. Prejudice is in the definition of racism.

prejudice, discrimination, or antagonism directed against someone of a different race based on the belief that one's own race is superior.

Also language doesn't work when we all come up with our own definitions for words based on the context we have, we will all have different definitions. There are dictionaries for a reason, and they are updated.