Americanism is the attachment or allegiance to the traditions, institutions, and ideals of the United States.
- Oxford Languages
In the words of Theodore Roosevelt, "Americanism is a question of spirit, conviction, and purpose, not of creed or birthplace."[3]

The years from the end of the 
Civil War to the end of World War II brought new meaning to the term "Americanism" to millions of immigrants coming from Europe and Asia. Those were times of great economic growth and industrialization, and thus brought forth the American scene consisting of "industrial democracy" and the thinking that the people are the government in America. Since then, the success of the American nation has brought tremendous power to the notion of Americanism.[1]
 - Wikipedia