Essentially they are exactly the same thing.
Labor unions are sometimes more associated with a specific company or group of people. Whereas a trade union may correspond to the entire network of people that are in that profession.
An association is a union of persons or companies for a common purpose or object. Like an employees association. A federation is a union of various unions. Like Federation of Chambers of Commerce or Federation of various Trade unions (may be bank employees unions, civil aviation employees unions, government employees unions, etc.)
Usually the unions represent labour and the management represent the employers.
Employers dont have unions.
The Wagner Act gave labor unions government support. It created a system to arbitrate disputes between unions and employers.
Employers grew more suspicious of labor unions.
The unions have a right to negotiate with employers for better pay, terms and working conditions.
The National Labour Relations Act
Action taken by employers to keep unions from forming is called
Free Association of German Trade Unions was created in 1897.
Free Association of German Trade Unions ended in 1919.
Oh, in europe, unions do not pretend not to be political parties. In the USA, unions pretend not to be agents of a political party.
Collective bargaining is negotiating terms between employers and employees. This happens many times between employers and labor union representatives.