Co ‧ per ‧ ni ‧ can sys ‧ tem, the /kəʊˈpɜːnɪkən ˌsɪstəm $ -ˈpɜːr-/ BrE AmE noun
the idea, first suggested by Copernicus, that the Earth and the other ↑ planet s all travel in circles around the sun. Before this it was believed, according to the Ptolemaic system, that the Earth was at the centre of the universe.