A defined group of employees of an employer, a majority of whom have chosen to be represented by a union, and on whose behalf a collective bargaining agreement is negotiated.

The process of negotiations between an employer and a union, representing a defined unit of the employer’s employees as a collective group, over the wages, hours, and other terms and conditions of employment for employees represented by the union.

The commonly used designation for a first-level organization of union members that is affiliated with a national or international union. While each union defines its own structure, a Local Union is often geographically or occupationally based and may represent one or more bargaining units. A local may be affiliated with a State or Regional unit, or directly with a national union. Those that are unaffiliated are called "Independent Unions."

The National Labor Relations Board conducts secret ballot elections various purposes, including in response to a petition from a union or a group of employees seeking to certify a labor organization as the exclusive collective bargaining representative for a defined unit of employees. Anti-union employers exploit the weaknesses in the NLRB election process to engage in union busting or union avoidance. Given that it is not necessary [see Voluntary Recognition] to prove majority status, it is commonly considered an anti-union tactic.

The process whereby an employer recognizes the union without going through an election. There is nothing preventing any employer from recognizing the union if more than 50% of the eligible employees have signed cards or a petition for union recognition. Usually, this is done by having a neutral third party check the signatures, sometimes called a "card check."

The commitment of an employer to remain “neutral” during a union organizing campaign (i.e., not oppose employees’ efforts to form a union). By law, employers are prohibited from coercing employees to support or oppose the union. In practice, many employers actively and effectively oppose unionization, legally and illegally. Neutrality is a commitment not to communicate anti-union sentiments or take any other action to undermine the union organizing effort or oppose their employees’ exercise of self-determination rights under federal labor law.

An individual, usually a unit member elected by the other members of the bargaining unit, whose responsibility is to support their fellow union members as a union representative. Steward responsibilities and duties vary by union, but often include keeping unit employees informed of union matters, attending and assisting employees in disciplinary meetings, and helping them to file and pursue grievances. Stewards also orient new employees to the union and help employees understand the Collective Bargaining Agreement. Also can be called "delegates" or "union representatives."

Many unions employ full-time staff to carry out a variety of functions for the union, including engaging with employers and employees in organizing and representing bargaining unit employees. Union staff train and support unit employees, sit at the bargaining table, and involve unit employees in other activities of the union. Common job titles are Organizer, Rep, or Business Agent.

The period of time that begins with official recognition of a union and typically continues until a Collective Bargaining Agreement takes effect is called the "status quo period." During this period, management may not change unit employees’ terms and conditions of employment unilaterally (i.e., without giving the union advance notice of the proposed change and a chance to negotiate before implementation.)

Conduct prohibited by the National Labor Relations Act is called an Unfair Labor Practice or "ULP." Employer ULPs include refusing to negotiate in good faith, interfering with or coercing employees in the exercise of their NLRA rights, and discriminating or retaliating against an employee because of their union views or activities. Unions can also commit Unfair Labor Practices, including by discriminating against or failing to fairly represent an employee.