Mainly North American: transferred use of the Scottish surname. This was brought to Scotland in or before the 13th century from a village (now deserted) called Hamilton or Hameldune, near Barkby in Leicestershire (named with Old English hamel ‘blunt, flat-topped’ + dūn ‘hill’). It is the surname of an enormously widespread and influential family, who acquired many titles, including the dukedom of Hamilton. The town near Glasgow so called is named after the family, not vice versa. Use as a given name seems to have begun in the United States in honour of Alexander Hamilton (?1757–1804), who was Secretary of the Treasury under George Washington and did much to establish the political and financial system on which the industrial growth and prosperity of the United States came to be founded. He was killed in a duel with the irascible Aaron Burr.
Spanish: habitational name from any of the various minor places, for example in the provinces of Burgos, Guadalajara, and Valladolid, named from Spanish padilla ‘frying pan’, ‘breadpan’ (Latin patella, a diminutive of patina ‘shallow dish’), a word which was commonly used in the topographical sense of a gentle depression.