What do we call the forced labor or service owed to a lord in medieval Europe?

The story behind the answer

This was the compulsory, unpaid labor that peasants owed to their lord or to the state, typically for a set number of days each year. It often meant repairing roads and bridges or working the lord’s demesne. That differs from a tithe (a religious tax, usually a tenth of produce) and from serfdom or villeinage, which describe a person’s legal status and broader obligations rather than this specific labor duty.

Widespread across medieval Europe and especially formalized in the Frankish and later French realms, it persisted into the early modern era and became infamous under the Ancien Régime. Because it pulled time away from peasants’ own fields and could be expanded in crises, it bred deep resentment and sparked periodic revolts, making its reduction or abolition a key demand in later reforms and revolutions.