Vassal

Obs. Someone who, by a series of formal acts, usually homage, commits themselves to serve another, usually receiving a fief in return.

The name given to the holder of a fief, bound to perform feudal service; this word was then always correlative to that of lord, entitled to such service.

The vassal himself might be lord of some other vassal. In aftertimes, this word was used to signify a species of slave who owed servitude, and was in a state of dependency on a superior lord.
   

This entry contains material from Bouvier's Legal Dictionary, a work published in the 1850's.