"Mass loss" refers to the reduction or decrease in the amount of a substance or material. It means that the object is losing weight or becoming lighter due to the loss of some of its particles or components. Full definition
This is confirmed by gravity satellite measurements over the past 9 years which find that the rate of ice mass loss has doubled over the last 9 years. (skepticalscience.com)
How much of it actually reaches the glaciers, and precisely how large its contribution is to the faster rates of mass loss observed in recent decades, remain open questions. (environmentalresearchweb.org)
At present, most mass loss from ice sheets occurs at their marine margins, through iceberg production and melting by the ocean. (eos.org)