In recent years much has been discussed regarding fluidization regimes, but most of the deliberations have been concerned with gas/solid (G/S) systems. Furthermore, designations of terminologies, such as phases, regions and regimes are far from being standardized. The present paper proposes a generalized scheme for regimizing fluidized systems, be they gas/solid (G/S) or liquid/solid (L/S), inclusive of the influences of the operating variables, and the physical properties of the particles and the fluid. The proposed scheme will be presented in conceptual terms and more or less in the chronological sequence of our growing understanding of fluidization.