A trade union is an association of workers that aims to secure economic benefits for its members by negotiating with employers collectively. The key characteristics of a trade union are that it is an association of employees in a particular industry or profession, membership is voluntary, it is a permanent body, and it acts collectively to address common interests like wages, benefits, and working conditions. Trade unions can help workers secure better pay and working conditions, get protection from exploitation and unfair treatment, and promote peaceful relations between workers and management. However, many trade unions in India suffer from problems like uneven growth across industries, low membership, and weak financial positions.