Def: an organized association of workers, often in a trade or profession, formed to protect and further their rights and interests; these became more widespread in the late 19th century, as a result of the spread of socialist ideas and a resistance against abuses in the factory system and urban issues
Sig: successfully led to widespread reform across many western countries, including a higher minimum-wage, child labor laws, better working conditions and hours; also further spread socialist ideas and led to widespread protests in several countries, including the U.S.