from The American Heritage® Dictionary of the English Language, 4th Edition
- n. An enlisted person in or a veteran of any of the U.S. armed forces, especially a person enlisted in the army.
- adj. Relating to or characteristic of an enlisted person.
- adj. Conforming to or in accordance with U.S. military regulations or procedures.
- adj. Issued by an official U.S. military supply department.
- adv. In strict accordance with military regulations or practices.
- transitive v. Slang To clean (barracks, for example) thoroughly for or as if for an inspection.
- abbr. galvanized iron
- abbr. gastrointestinal
- abbr. general issue
- abbr. Government Issue
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The ISO 3166-1 two-letter (alpha-2) code for Gibraltar.
- adj. 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.
- n. A member of the U.S. military.
- n. One who is demanding and strict, in the manner of a stereotypical member of the military.
- v. To clean aggressively.
- Galvanized iron.
- Government issue or General Infantry.
- abbr. Common misspelling of Gl., the prefix for Gliese catalog of nearby stars
From abbreviation of galvanized iron (applied to trash cans, etc.), later reinterpreted as government issue.(American Heritage® Dictionary of the English Language, Fourth Edition)
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. (Wiktionary)