A trade union is defined as a continuous association of wage-earners formed to maintain or improve working conditions through collective bargaining. There are several key characteristics of trade unions including registration with the registrar of trade unions, independence from employers, and affiliation with central trade union organizations. Trade unions serve both militant functions like negotiating wages and working conditions as well as fraternal functions like providing welfare benefits and education. They operate at both national and industry levels and can take various forms based on membership. Democratic participation and control by members is important for a trade union's effectiveness.