( in full the Industrial Workers of the World )
a US trade union of 43 organizations established in 1905 in Chicago . Its leaders called for a workers’ revolution. The IWW was most powerful from 1912 to 1917 when it had nearly 100 000 members (often called Wobblies). During World War I, its violent strikes were considered to be against the country’s war effort. The leaders were put into prison, and the IWW soon ended.