This points to a problem with our definition. For most people planets are anything spherical that’s too small to be a star and doesn’t orbit another one of those spherical non-stars. That’s certainly the definition this article uses.
I’m not really sure how one could be confused by that. One might be petty about it – but confused?
This is a common way of describing things. Something is described in terms of something else, the properties that are different are pointed out separately. One might describe an e-book in terms of a book made of paper, pointing out, along the way, the important differences. Since e-books and books made of paper are very similar nobody would protest if, in that context (and after the explanation of the differences), the naked word 'book' would be used to refer to e-books.