BEM (basic empty mass) = the mass of an aeroplane plus standard items such as: emergency oxygen, fire extinguisher, oil in engin and unusable fuel fluids
BEM not include usable fuel and not passenger.
DOM (dry operation mass) = is the total mass of the aeroplane ready for a operation (A/M operative), with crew and crew baggage, foods and water
DOM not include usable fuel and traffic load (TL)
OM (operating mass) = DOM + fuel but not include traffic load (TL).
TL (traffic load) = sum of pay load passenger, baggage, and cargo.
Not include any non-revenue load.
ZFM (zero fuel mass) = DOM + TL but not include fuel.
MZFM (maximum zero fuel mass) = maximum mass of an airplane with no usable fuel.
TAXI MASS = RAMP WEIGHT
TOM (take off mass) = is the mass of an areoplane including everiting ready for take off run.
RTOM (regulated take off mass) = is the TOM but performance limitated.
MSTOM (maximum structural take off mass) = is the max structural for take off run.
MSLM (maximum structural landing mass) = is the maximum permissible total airplane mass on landing (normal).
Useful/disposable load = the sum of traffic load (TL) and fuel on board.