What is the difference between associations and unions? - CIEA Online

From International Federation of Professional and Technical Engineers: “Associations are organizations of people with a common interest or purpose. People form associations for a number of reasons such as retirement issues, professional certification, and even employee welfare or work issues. A union is a type of association, though with one major difference: members of a union have the legal right to engage in collective bargaining with an employer, and the employer is legally obligated to bargain with the union.”