The meaning of the word American in the English language varies according to the historical, geographical, and political context in which it is used. American is derived from America, a term originally denoting all of the Americas (also called the Western Hemisphere). In some expressions, it retains this Pan-American sense, but its usage has evolved over time and, for various historical reasons, the word came to denote people or things specifically from the United States.
In modern English, American generally refers to persons or things related to the United States of America; among native English speakers this usage is almost universal, with any other use of the term requiring specification. However, some linguists in the past have argued that "American" should be widened to also include people or things from anywhere in the American continents.
The word can be used as either an adjective or a noun (viz. a demonym). In adjectival use, it means "of or relating to the United States";