The term Yankee and its contracted form Yank have several interrelated meanings, all referring to people from the United States. Its various senses depend on the context, and may refer to New Englanders, residents of the Northern United States, or Americans in general. According to the Oxford English Dictionary, it is "a nickname for a native or inhabitant of New England, or, more widely, of the northern States generally".

Outside the United States, Yank is used informally to refer to an American person or thing. It has been especially popular in the United Kingdom, Ireland, Canada, South Africa, Australia, and New Zealand where it may be used variously with uncomplimentary overtones or cordially. In the Southern United States, Yankee is a derisive term which refers to all Northerners, and during the American Civil War was applied by Confederates to soldiers of the Union army in general. Elsewhere in the United States, it largely refers to people from the Northeastern states, but especially those with New England cultural ties, such as descendants of colonial New England settlers, wherever they live. Its sense is sometimes more cultural than geographical, emphasizing the Calvinist Puritan Christian beliefs and traditions of the Congregationalists who brought their culture when they settled outside New England. The speech dialect of Eastern New England English is called "Yankee" or "Yankee dialect".