A trade union (British EnglishAustralian EnglishNew Zealand EnglishSouth African English / Caribbean English; also trades union), labour union (Canadian English), or labor union (American English) is an organization of workers who have come together to achieve common goals such as protecting the integrity of its trade, improving safety standards, achieving higher pay and benefits such as health care and retirement, increasing the number of employees an employer assigns to complete the work, and better working conditions. The trade union, through its leadership, bargains with the employer on behalf of union members ( members) and negotiates labour contracts (collective bargaining) with employers. The most common purpose of these associations or unions is "maintaining or improving the conditions of their employment". This may include the negotiation of wages, work rules, complaint procedures, rules governing hiring, firing and promotion of workers, benefits, workplace safety and policies.