Indentured servitude is a form of labor in which a person (an indenture) agrees to work without salary for a specific number of years for eventual compensation or debt repayment. Historically, it has been used to pay for apprenticeships, typically when an apprentice agreed to work for free for a master tradesman to learn a trade (similar to a modern internship, but for a fixed length of time usually seven years). Later it was also used as a way for a person, to pay the cost of transportation to colonies in the Americas.