Left–right political spectrum
The terms left-wing and right-wing are widely used in the United States, but as on the global level there is no firm consensus about their meaning. The only aspect that is generally agreed upon is that they are the defining opposites of the United States political spectrum. Left and right in the U.S. are generally associated with liberal and conservative respectively, although the meanings of the two sets of terms do not entirely coincide. Depending on the political affiliation of the individual using them, these terms can be spoken with varying implications. A 2005 poll of 2,209 American adults showed that "respondents generally viewed the paired concepts liberals and left-wingers and conservatives and right-wingers as possessing, respectively, generally similar political beliefs", but also showed that around ten percent fewer respondents understood the terms left and right than understood the terms liberal and conservative.
Left-wing politics
The term was later applied to a number of movements, especially republicanism during the French Revolution in the 18th century, followed by socialism, communism, anarchism and social democracy in the 19th and 20th centuries. Since then, the term left-wing has been applied to a broad range of movements including civil rights movements, feminist movements, anti-war movements and environmental movements, as well as a wide range of parties. According to former professor of economics Barry Clark, "[leftists] claim that human development flourishes when individuals engage in cooperative, mutually respectful relations that can thrive only when excessive differences in status, power, and wealth are eliminated".