The "Vietnam War" is American terminology. In Vetnam it is known as The American War. It is obvious, too, that Americans learned NOTHING from their experience.
In the 1950's the United States began to send troops to Vietnam. During the following 25-years the ensuing war would create some of the strongest tensions in US history. Almost 3 million US men and women were sent thousands of miles to fight for what was a questionable cause. In total, it is estimated that over 2,5 million people on both sides were killed.
The Americans were fighting the same enemy the French did in 1946-54, the Viet Minh. The Yanks however, considered it humiliating to fight an enemy with such a namby-pamby name. So they christened them the Viet Cong.