What does G.I. mean, as in G.I. Joe?

Origin of the term is in fact galvanized iron --

GI or G.I. is a term describing a member of the US armed forces or an item of their equipment. It may be used as an adjective or as a noun. The term is often thought to be an initialism of "Government Issue" but the origin of the term is in fact galvanized iron after the letters "GI" that used to denote equipment such as metal trash cans made from it in U.S. Army inventories and supply records.


https://en.wikipedia.org/wiki/GI_%28military%29

Well, my grandfather always said it stood for "government issue", but come to find out the agreed-upon etymology is "galvanized iron" - the initials were embossed on so many things in WWI that the name stuck.

https://en.wikipedia.org/wiki/GI_%28military%29

I use Wikipedia a lot and find it surprisingly reliable, although of very uneven quality regarding spelling and style. On this question, however, I will cite Colin Powell against Wiki. He says "G.I." means "government issue," and I choose to believe he is a higher authority than Wiki. Admittedly, what would the Chief of Staff know about the common G.I.? Etymology is a fun puzzle to study, but fraught with false turns.

When the action figure "G.I. Joe" came out, (yes, over 40 years ago) I read what I believed was an authoritative book that said it meant "government issue." I can't remember the title or author.

GI Government Issue (as in GI Joe)
GI Gastrointestinal
GI Gibraltar
GI Glycemic Index
GI General Issue
GI Galvanized Iron
GI Granuloma Inguinale (aka: Donovanosis)
GI Granulomatous Inflammation(chronic inflammation)
GI Guaranteed Insurability (insurance)
GI Geophysical Institute
GI Game Informer
GI Goethe-Institute
GI Global Illumination (graphic art)
GI Geographical Indications
GI Gilligan's Island (TV show)

http://www.acronymfinder.com/af-query.asp?String=exact&Acronym=GI&Find=Find

Then there is the old "General Infantry".

I don't see that it is much of a stretch from G.I. Galvanized Iron to G.I. Government Issue. Nevertheless, "Historical Dictionary of the U.S. Army" By Jerold E. Brown states:

The use of the term G.I. originated in the 1930s to designate government issue items provided to U.S. Army Troops. It became more prevalent when the Army began to mobilize in 1940.

Most people nowadays know that a G.I. is an American soldier and that the term is popularly associated with the Second World War, but few know what the abbreviation G.I. originally stood for or that the term predates WWII by some decades.

G.I. was originally a semi-official U.S. Army abbreviation for galvanized iron, used in inventories and supply records. It dates to at least 1907 and is commonly found in records from the First World War. From a 1917 entry in Col. Frank P. Lahm’s World War I Diary, published in 1970:

[Lympe, England] is a large depot where machines are delivered for forwarding to France. 12 large hangers [sic], brick, G.I., about 75 ft wide by 150 ft long.

https://www.etymonline.com/word/g.i.

It's entirely possible there isn't just ONE answer.

More on the galvanized iron angle; notice one source claims the "trash cans" were German shells. Whatever.

"GI. Government Issue. A member of the military services. Originally the stamp on buckets indicating galvanized iron.
http://4mermarine.com/USMC/dictionary.html

"Origin:
1915–20; orig. abbr. of galvanized iron, used in U.S. Army bookkeeping in entering articles (e.g., trash cans) made of it; later extended to all articles issued (as an assumed abbrev. of government issue) and finally to soldiers themselves."
http://dictionary.reference.com/browse/GI

Origin: 1917
For much of the twentieth century, GI has been the common designation for the American fighting man--or woman. However, the GI was born early in the century not as a soldier but as a trash can. Originally the initials GI formed an abbreviation that stood for the material from which a trash can was made, galvanized iron, and its source, government issue. During World War I, when the term first came to attention in the American Expeditionary Force, GI can was the doughboys' trash talk for a German artillery shell. "After dark that night," went one account, "Fritz came over and started dropping those famous G.I. cans." And another: "We crossed the river on a span of a sunken bridge that was struck by a G.I.C." German shells were also just plain GIs, as in this 1918 poem: "There's about two million fellows, and there's some of them who lie/Where eighty-eights and G.I.'s gently drop."

Shortly before the start of World War II, the GI (for government issue, or general issue) became human. There had been GI soap, GI shoes, and GI clothes; now there was the GI soldier, soon shortened to plain GI. By the time World War II began, doughboy (1865) had been completely displaced by the more versatile GI, the term that remains in use today. And whatever the effects of GI food, the military GI has nothing to do with the gastrointestinal GI of the medical profession.
http://www.answers.com/topic/gi

Nice discussion about the differences between GI (Galvanized Iron) and GI (Government Issue) but the question is how does the GI connect with GI Joe. That usage is from WW II and means Government Issue Joe. The British use a similar coinage to call their soldiers Tommy Atkins (or just Tommy). ................ https://en.wikipedia.org/wiki/Tommy_Atkins