High Quality Content by WIKIPEDIA articles! Pax Americana (Latin for "American Peace") is a term applied to the historical concept of relative peace in the Western Hemisphere and later the Western world resulting from the preponderance of power enjoyed by the United States starting around the start of the 20th century. Although the term finds its primary utility in the later half of the 20th century, it has been used in various places and eras, such as the post-Civil War era in North America and globally during the time between the World Wars.