serfs

/S ER1 F S/
noun
  1. 1

    A partially free peasant of a low hereditary class, attached like a slave to the land owned by a feudal lord and required to perform labour, enjoying minimal legal or customary rights

  2. 2

    A similar agricultural labourer in 18th and 19th century Europe

  3. 3

    (strategy games) a worker unit

Source: https://en.wiktionary.org/wiki/serf, https://en.wiktionary.org/wiki/serfs