The Collaborative International Dictionary of English v.0.48:
Populism \Pop"u*lism\, n. (U. S. Politics) The political doctrines advocated by the People's party. [Webster 1913 Suppl.]WordNet (r) 3.0 (2006):
populism n 1: the political doctrine that supports the rights and powers of the common people in their struggle with the privileged elite