What is an indentured servant?

Contracted Labor, particularly of the 1500s and 1600s era, notably in colonial North America. Later much of the labor was taken over by Slaves.
Indentured referred to boiler plate printed contracts between Master and Servant in which the 2 copies of the same were folded together and indentured at the margins before separation of the document and retained by each party. Verification of authenticity of either could easily be made at a later time by superposition of the two. Indentured servitude was a generally a British custom and distinctive of early North America.
The Master took on responsibilities to provide food, clothing, shelter, transportation and general maintenance of health to the Servant. There could also be a payout of goods or money at the end of the contract. The Servant to provide obedient labor (sometimes skilled) for the Master usually for a specific time period (often several years). This labor was often back breaking field labor. Indentured servants were often very poor and uneducated.
Legislation provided a limited set of rights for the Servants. The legislation was written by people who were Masters attempting to provide a stable workforce. In America the harsh conditions often were fatal to any type of Laborer. The cultivation of Tobacco created a great demand for labor in the new Colonies. Indentured servitude was a traditional way of raising labor for such a purpose. The children of indentured servants were free men until they also were contracted.
Slavery had the advantage of the laborer having no rights and producing children that were also slaves.