How about the belief that different races [not one in particular] are better or worse, on average, according to many different metrics [none of which constitutes absolute "superiority"] and that when deciding how to act it is sometimes proper to incorporate what we believe to be true about these differences.

I'll be honest - that's where I am. I think most people would regard me as a racist, which is stupid because my position is just the plain truth.

Yours is a fairly good definition but I think there are a couple of other ingredients worth spelling out more explicitly:

There's the tribalism: forming in-groups and out-groups on the basis of ethnicity is conceptually distinct from having beliefs about ethnic groups. (Though of course they tend to go together in practice.)

And there's the obsession: I think part of racism is the idea of "seeing the world through race-coloured glasses"; treating people as exemplars of their race instead of noticing their individual characteristics; an overeagerness to explain observations and events in terms of the races of the people involved - to reduce history to a story about battling races.

Again, this correlates closely with 'beliefs about superiority' and 'tribalism', but is conceptually distinct.