The New Dictionary of Cultural Literacy, Third Edition. 2002.
left-wing
A descriptive term for an individual or a political faction that advocates liberal, radical, or even revolutionary policies, usually in favor of overcoming social inequalities. In the United States, left-wing groups generally support federal social welfare programs designed to open opportunities to all citizens. (Compareright-wing.)
Although both major political parties in the United States have left-wing factions, left-wing policies are usually associated with the Democratic party.