1a member of the British reforming and constitutional party that sought the supremacy of Parliament and was eventually succeeded in the 19th century by the Liberal Party.Compare with Tory (sense 1 of the noun).
2a supporter of the American side during the War of American Independence.
a member of an American political party in the 19th century, succeeded by the Republicans.
3a 17th-century Scottish Presbyterian.
4 [as modifier] denoting a historian who interprets history as the continuing and inevitable victory of progress over reaction.
mid 17th century(in Whig (sense 3)): probably a shortening of Scots whiggamore, the nickname of 17th-century Scottish rebels, from whig 'to drive' + mare1