Knickerbocker a New Yorker, taken as a descendant of the original Dutch settlers in New York. The term comes from Diedrich Knickerbocker, pretended author of W. Irving's History of New York (1809).

The term knickerbockers for loose-fitting breeches gathered at the knee or calf is said to have arisen from the resemblance of knickerbockers to the knee breeches worn by Dutch men in Cruikshank's illustrations in Irving's book.

knickerbockers loose-fitting breeches. XIX. f. name of Diedrich Knickerbocker, the pretended author of Washington Irving's ‘History of New York’ (1809). The name is said to have been given to the garment from its resemblance to the knee-breeches of the Dutchman in Cruikshank's illustrations to the History. abbrev. knickers XIX.