Pronunciation: (u-mer'i-kun),[key] —adj. 1. of or pertaining to the United States of America or its inhabitants: an American citizen. 2. of or pertaining to North or South America; of the Western Hemisphere: the American continents. 3. of or pertaining to the aboriginal Indians of North and South America, usually excluding the Eskimos, regarded as being of Asian ancestry and marked generally by reddish to brownish skin, black hair, dark eyes, and prominent cheekbones.
—n. 1. a citizen of the United States of America.
2. a native or inhabitant of the Western Hemisphere.
3. an Indian of North or South America.
4. See American English. 5. a steam locomotive having a four-wheeled front truck, four driving wheels, and no rear truck. See table under Whyte classification.