G.I. Stands for Government Issue
SEAL stands for SEa,Air,and Land,all the ways a Navy SEAL can carry out his mission.
G.I.=Galvanlized Iron (honest). G.I. Were the initials stamped on US metal rubbish bins (trash cans), denoting what they were made out of. Infantrymen in World War I joked that they were treated like expandable government issue trash cans; so they called themselves G.I.'s. Hence, it is not an official/proper name for military members. The name is also sometimes interpreted as General Infantry, Government Issue, or Ground Infantry. G.I.s are always the main type of soldier, enlisted, those who might see front-line armed battle. Not paper pushers or officers. SEAL=(Unites States Naval) Sea Air and Land (Special Operations Forces). The training to become a SEAL is extremely demanding and takes about 11 months. There is a high attrition/failure rate for people trying to be SEALs. Most of the training takes place at Coronado Naval Base (San Diego). SEALs also learn parachuting with the U.S. Army for three weeks. At any one time the U.S. Navy has about 1000 trained SEALs (out of a total force of approx. 345,000 active personnel and 145,000 reserves.