If you follow the news, you'll hear a lot about negotiations between employers and trade unions. Sometimes there may even be agitation on behalf of the unions reported in the news, such as a representative speaking from atop a turret, punching a police officer, or blocking customers from entering the business while the employees are on strike. This may be confusing to you if you don't really understand what a trade union is or what it's supposed to accomplish for the workers. This article can help make things clearer.
Basically, a trade union is a group of people with the same profession or employer who have joined together to give themselves a position of greater power from which to negotiate from when disputes with the employer arise. The threat of one person stopping work if the adhesive name tags rule isn't revoked has little effect on a company's bottom line. But the threat of ALL their employees stopping work over the same issue is enough to bring them to the negotiating table to talk about a solution. This is called collective bargaining.
Trade unions arose in England during a time when employers had all the power and the employees had none. Rich owners of factories and mines could dictate whatever sort of working conditions and wages they wanted to their destitute employees, and if they complained, they would just be replaced. It was only once the employees joined together, utilizing the theory that in unity there was strength, that conditions began to improve. This traditionally antagonistic relationship is why some people with real estate jobs may be hesitant to join a union or employ members of a union.
The purpose of a union isn't just to wring concessions from an employer in the case of an emergency. Unions also help protect the job security of the workers who belong to it and help ensure that their incomes rise along with the cost of living. They make sure any rules the government makes that affect their jobs are fair and that no employee can be unfairly dismissed. They can also lobby the government for laws which will benefit the members of the union and help union members with insurance and worker's compensation claims.
Not every profession has a union. For example, a dentist who works for himself has no need for a trade union. However many professions do. The ones that are the most powerful and are in the news most often include the CAW or Canadian Auto Workers union, CUPE or the Canadian Union of Public Employees, the Canadian Postal Workers Union, the various provincial teachers' unions, and ACTRA or the Association of Canadian Cinema, Television, and Radio Artists.