A trade union (British English) or labor union (American English) is an organization of workers who have banded together to achieve common goals such as better working conditions. The trade union, through its leadership, bargains with the employer on behalf of union members (rank and file members) and negotiates labour contracts (collective bargaining) with employers. This may include the negotiation of wages, work rules, complaint procedures, rules governing hiring, firing and promotion of workers, benefits, workplace safety and policies. The agreements negotiated by the union leaders are binding on the rank and file members and the employer and in some cases on other non-member workers.

Originating in Europe, trade unions became popular in many countries during the Industrial Revolution, when the lack of skill necessary to perform most jobs shifted employment bargaining power almost completely to the employers' side, causing many workers to be mistreated and underpaid. Trade union organizations may be composed of individual workers, professionals, past workers, or the unemployed. The most common, but by no means only, purpose of these organizations is "maintaining or improving the conditions of their employment".

Over the last three hundred years, many trade unions have developed into a number of forms, influenced by differing political objectives. Activities of trade unions vary, but may include:

• Provision of benefits to members: Early trade unions, like Friendly Societies, often provided a range of benefits to insure members against unemployment, ill health, old age and funeral expenses. In many developed countries, these functions have been assumed by the state; however, the provision of professional training, legal advice and representation for members is still an important benefit of trade union membership.
• Collective bargaining: Where trade unions are able to operate openly and are recognized by employers, they may negotiate with employers over wages and working conditions.
• Industrial action: Trade unions may enforce strikes or resistance to lockouts in furtherance of particular goals.
• Political activity: Trade unions may promote legislation favorable to the interests of their members or workers as a whole. To this end they may pursue campaigns, undertake lobbying, or financially support individual candidates or parties (such as the Labour Party in Britain) for public office.

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See also:

• Society: Issues: Labor (102)
• Society: Law: Legal Information: Labor and Employment Law (72)
• Society: Politics: Anarchism: Anarcho-Syndicalism (22)
• Society: Work: Labor-Management Relations (46)

• Union Jobs Clearinghouse
  unionjobs.com
  Central site for posting current openings for staffing and trades positions in organized labor.
• Union Resource Network
  unions.org
  Union internet services including Web hosting, promotion, and design, Internet access, and a union database provided by CWA members (CWA-TNG, Local 14761).
• MGGBGS Labor Union Page
  mgbgs.com
  A listing of labor unions maintained by the law firm Mooney, Green, Gleason, Baker, Gibson and Saindon.