The formation of a theoretical concept is brought about by establishing axioms of a scientific theory that determine the meaning of that concept. We are familiar with this idea from the work of Carnap and others. All formal accounts, however, of the formation of theoretical concepts assume the corresponding scientific theory to be fully consistent with all related theories in all applications. This condition is rarely met, even by highly successful theories. Hence, a formal account of paraconsistent concept formation is needed. I shall devise such an account using a structuralist approach to belief revision. In doing so, I shall address the more general problem of a logical analysis of paraconsistent reasoning in science.