Definition
The term work visa refers to a document that allows the holder to be admitted into another country for a specific purpose. A visa can be obtained from an Embassy or Consulate of the country the individual wishes to visit.
Explanation
When working abroad, an individual may be required to obtain a visa before traveling to a foreign country. Visas are issued by consular officers, and indicate eligibility to seek entry into a country for a specific purpose. That being said, a visa does not guarantee entry into a country. The exact rules of entry will vary by country; however, visas typically fall into two broad categories:
Nonimmigrant: used by an individual that does not intend to remain in the country to which they're visiting. This type of visa is normally issued to tourists, students, and temporary workers. Countries can also issue temporary, seasonal, and exchange worker visas.
Immigrant: used by individuals that plan to permanently reside in the country they're visiting.
When issued, a visa becomes part of the traveler's passport, which is a document that is used for identification purposes. A passport allows the traveler to return to their country of citizenship.