I think that outside of ancient anthropology and archaeology, the term "civilization" is at best useless an at worst harmful and offensive. If you're using the term to distinguish a historical group of people who share some cultural, ethnic, societal, and geographic similarities, and can't be described better by any other term, then I'd say it's legitimate use of the term (for example, I think it's right to call the Sumerians a civilization, as they spoke the same language, worshipped the same gods, inhabited the same land, and had trade and diplomatic relations between each other, despite never clearly organizing themselves as a unique separate entity, political or otherwise, that can actually be called "the Sumerian civilization"). Using it in later historical contexts makes usage of the term tricky at best (I mean, who was the civilization of medieval Europe? Was each principality its own civilization? Was each kingdom or empire? or was all of Christian Europe one civilization? Based on what distinction?), and if you think the term is still relevant for describing modern societies then, well, boy have I got some news for you.