The maximum zero fuel weight (MZFW) is the maximum weight allowed before usable fuel and other specified usable agents (engine injection fluid, and other consumable propulsion agents) are loaded in defined sections of the aircraft as limited by strength and airworthiness requirements.
The maximum zero-fuel weight (MZFW) signifies the utmost allowable load before adding usable fuel and specific consumable items like engine lubricants or propulsion agents, all while maintaining safety and airworthiness criteria.