Hmm. I'd say that they'd be called brunettes. I have some African American ancestry, and my siblings and I all have brown hair. I asked, and my sister considers herself to be a brunette. Although, we are often mistakenly thought to have black hair, when really, it's only dark brown (with a mix of other colours here and there). It's a little bit annoying when people insist that my hair is black when I explain to them that it's not. Be careful to make sure that the person you're referring to as a brunette actually has brown hair, as it can be a bit difficult to make the distinction.