COMPRESSOR: It is a device used to increase the pressure of a compressible fluids like gas.
PUMP: It is a device used to increase the pressure of a incompessible fluids like water.
FLUID: It is a substance which undergoes deformation for the smallest action of shear force. Both gas and liquid comes under the catagory of fluid.
COMPRESSIBLE: Density will not be same. eg:gases
INCOMPRESSIBLE: Density remains constant. eg: water (1000 kg/m^3) i e density of water is constant the value is mentioned above.