A “migrant worker” is a person who either migrates within their home country or outside it to pursue work such as seasonal work. Migrant workers usually do not have an intention to stay permanently in the country or region in which they work.
Migrant workers who work outside their home country are also called foreign workers. They may also be called expatriates or guest workers, especially when they have been sent for or invited to work in the host country before leaving the home country.
The International Labour Organization estimated in 2014 there were 232 million international migrants worldwide who were outside their home country for at least 12 months and approximately half of them were estimated to be economically active (i.e. being employed or seeking employment). Some countries have millions of migrant workers. Some migrant workers may be illegal immigrants. Some may be slaves.