The origins of this popular nickname are somewhat murky. A popular theory links the term to the early 20th century, when “G.I.” was stamped on military trash cans and buckets. The two-letter abbreviation stood for the material from which these items were made: galvanized iron. Later, the definition of GI broadened and during World War I it was used to refer to all things Army-related, according to “Origins of the Specious: Myths and Misconceptions of the English Language” by Patricia T. O’Conner and Stewart Kellerman. When this happened, GI was reinterpreted as “government issue” or “general issue.”

The prevalence of the term led soldiers in World War II to start referring to themselves as GIs. Some servicemen used it as a sarcastic reference symbolizing their belief that they were just mass-produced products of the government. During the war, GI Joe also became a term for U.S. soldiers. Cartoonist Dave Breger, who was drafted into the Army in 1941, is credited with coining the name with his comic strip titled “G.I. Joe,” which he published in a weekly military magazine called Yank, beginning in 1942. In 1964, U.S. toy company Hasbro, after taking note of competitor Mattel’s huge success with the Barbie doll (launched in 1959), debuted “G.I. Joe,” a military-themed line of action figures for boys.

Meanwhile, in June 1944, President Franklin Roosevelt signed the Servicemen’s Readjustment Act, which became commonly known as the GI Bill. The famous legislation provided a range of benefits for returning World War II veterans, including funding for college, home loans and unemployment insurance.