A perennial mass of ice, and possibly firn and snow, originating on the land surface by the
recrystallization of snow or other forms of solid precipitation and showing evidence of past or present
flow.
For mass-balance purposes glaciers are delineated, when possible, by outlines across which there
is no flow, so that transfer of mass as ice across those outlines is zero. Any change of the outline
during the study period must be allowed for appropriately. If part of the outline fails the no-flow test,
such as at a grounding line, the ice discharge must be included as a component of the mass balance.
In contrast to what is natural in dynamic glaciology and glacial geomorphology, for mass-balance
purposes the glacier consists only of frozen water. Sediment carried by the glacier is deemed to be
outside the glacier. Meltwater in transit or in storage, for example in supraglacial lakes or subglacial
cavities, is also regarded as being outside the glacier.
Glaciers may contain or consist of other glaciers. The more generic term glacier complex is
available for objects that may be divisible into more than one glacier, and the term ice body is
available for any object that is made mainly of ice and may or may not be a glacier

Glossary of glacier mass balance and related terms. Working Group on Mass-balance Terminology and Methods of the International Association of Cryospheric Sciences (IACS)

Credits: Guilhem Vellut

https://en.wikipedia.org/wiki/Glacier#/media/File:Baltoro_glacier_from_air.jpg