Agency staff
Freelancers, Consultants and Contractors
Zero-hour contracts

United States
For purposes of U.S. federal income tax withholding, 26 U.S.C. § 3401(c) provides a definition for the term "employee" specific to chapter 24 of the Internal Revenue Code:

"For purposes of this chapter, the term "employee" includes an officer, employee, or elected official of the United States, a State, or any political subdivision thereof, or the District of Columbia, or any agency or instrumentality of any one or more of the foregoing. The term "employee" also includes an officer of a corporation." This definition does not exclude all those who are commonly known as employees. "Similarly, Latham’s instruction which indicated that under 26 U.S.C. § 3401(c) the category of ‘employee’ does not include privately employed wage earners is a preposterous reading of the statute. It is obvious that within the context of both statutes the word ‘includes’ is a term of enlargement not of limitation, and the reference to certain entities or categories is not intended to exclude all others. "Employees are often contrasted with independent contractors, especially when there is dispute as to the workers entitlement to have matching taxes paid, workers compensation, and unemployment insurance benefits.
Although most work occurs following this structure, the wage work arrangements of  CEOs, professional employees, and professional contract workers are sometimes conflated with class assignments, so that "wage labor" is considered to apply only to unskilled, semi-skilled or manual labor. Wage slavery
Wage labor, as institutionalized under todays market economic systems, has been criticized, especially by socialists, using the pejorative term wage slavery. Socialists draw parallels between the trade of labor as a commodity and slavery. Cicero is also known to have suggested such parallels.The American philosopher John Dewey posited that until "industrial feudalism" is replaced by "industrial democracy", politics will be "the shadow cast on society by big business". Thomas Ferguson has postulated in his investment theory of party competition that the undemocratic nature of economic institutions under capitalism causes elections to become occasions when blocs of investors coalesce and compete to control the state plus cities. Employment contract
Australia
Australian employment has been governed by the Fair Work Act since 2009. Bangladesh
Bangladesh Association of International Recruiting Agencies (BAIRA) is an association of national level with its international reputation of co-operation and welfare of the migrant workforce as well as its approximately 1200 members agencies in collaboration with and support from the Government of Bangladesh. Canada
In the Canadian province of Ontario, formal complaints can be brought to the Ministry of Labour. In the province of Quebec, grievances can be filed with the Commission des normes du travail.