Short answers, pulled from the story.
Feudalism was a combination of customs and systems that flourished in medieval Europe from the 9th to the 15th centuries. It structured society around relationships derived from holding land in exchange for service or labour, revolving around lords, vassals, and fiefs.
François Louis Ganshof's classic 1944 definition describes only the reciprocal legal and military obligations of the warrior nobility, centered on lords, vassals, and fiefs. Marc Bloch's broader 1939 definition includes all three estates of the realm: the nobility, the clergy, and the peasantry bound by manorialism.
The word feudal comes from the medieval Latin feudum, meaning fief, first attested in a charter of Charles the Fat in 884. The adjective feudal was in use by at least 1406, while the noun feudalism appeared by the end of the 18th century, with John Whitaker first introducing the word in 1771.
France abolished the feudal system on the night of the 4th of August 1789, when the National Assembly declared it ended entirely, followed by a decree of the 11th of August 1789. Most of the military aspects of feudalism had already ended by about 1500.
In 1974, Elizabeth A. R. Brown rejected feudalism as an anachronism with no basis in medieval reality, calling it a modern construct read back into the record. Susan Reynolds expanded this argument in Fiefs and Vassals in 1994, and critics say the many uses of the term have deprived it of specific meaning.
A vassal became bound to a lord through a commendation ceremony comprising an act of homage and an oath of fealty. During homage the vassal promised to fight at the lord's command, while the lord agreed to protect the vassal from external forces.