In this paper a number of reuse approaches for circuit design are analysed. Based on this analysis an algebraic core model for discussion of a general reuse strategy is proposed. Using this model, the aim is to classify different reuse approaches for circuit design, to compare the applied terms and definitions, and to formulate classes of typical reuse tasks. In a practical application with focus on retrieval and parameterisation techniques, this model is on the way to being applied to DSP design issues.