In feudal societies, a system of servitude for those who are bound to a hereditary plot of land and to the will of his landlord and who could be sold or otherwise transferred to someone else with the land.

Serfs differed from slaves in that slaves could be bought and sold without reference to the land; however, serfs changed lords only when the land they worked on changed to ownership.

Serfdom was the enforced labor of serfs on the fields of landowners, in return for protection and the right to work on their leased fields; and it involved not only work in fields, but also various other activities; such as, forestry, mining, transportation (both land and river), and various crafts.