Given to a soldier by the army (as an item), rather than brought from home; or used by the army (as a procedure), and different from its civilian counterpart
A GI is a soldier in the United States army. Gibraltar (in Internet addresses). gill (liquid measure). a soldier in the US army, especially during the Second World War
(abbreviation.) GI was originally an initialism for Galvanized Iron; during the 1930s the usage expanded to stand for Government Issue; by World War II it had become a nickname for the military personnel themselves.