The measurement used by freight carriers to determine the price you will pay to ship your goods. It can be either the gross weight (i.e. actual weight) or the volumetric weight (i.e. dimensional weight) of the shipment, whichever is greater.
Carriers will use the actual weight and the volume of your shipment to calculate a "weight equivalent" that serves as the volumetric weight. The method used to calculate volumetric weight varies by mode of transportation or trade lane.
You may see that the volume or weight listed on your bill isn't the same as the volume you had provided when you booked your shipment. This can happen when your freight takes up more space than you had anticipated due to palletization, or even if you used Styrofoam chips instead of your usual air-filled plastic to protect your items. It's important to consider all of these things when you're planning for the cost of your shipment.