The use of a lossy variable termination becomes an undesirable necessity in certain measurement situations, while in others its deliberate use facilitates the measurement of low-loss structures. In both of these cases, the present approach permits the analysis of the data to proceed in a manner identical to that employed when lossless short-circuits are used, i.e. with already familiar procedures. It results in a composite 4-terminal network from which the desired parameters are separated using particularly simple relations.Applications are made to a variety of measurements, including those of dissipative, lossless and symmetric 4-terminal networks, attenuation and attenuation constants.