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Dictionaries Used
Terms about European Backgrounds of Feudalism (Europe in the Middle Ages or c. 500 AD to 1300 to 1500 AD)
feudalism
manor (land held by the lord in feudalism)
vassal
Serf

Dictionaries Used
Unless a different dictionary is specified, all definitions are from Merriam-Webster’s Online Dictionary at http://www.merriam-webster.com/

Terms about European Backgrounds of Feudalism (Europe in the Middle Ages or c. 500 AD to 1300 to 1500 AD) 
From Merriam-Webster’s Online Dictionary at http://www.merriam-webster.com/
feudalism
Main Entry: feu·dal·ism 
Pronunciation: \ˈfyü-də-ˌli-zəm\
Function: noun 
Date: circa 1818
1 : the system of political organization prevailing in Europe from the 9th to about the 15th centuries having as its basis the relation of lord to vassal with all land held in fee and as chief characteristics homage, the service of tenants under arms and in court, wardship, and forfeiture
2 : any of various political or social systems similar to medieval feudalism
manor (land held by the lord in feudalism)
Main Entry: man·or 
Pronunciation: \ˈma-nər\
Function: noun 
Etymology: Middle English maner, from Old French manoir, from manoir to sojourn, dwell, from Latin manēre — more at mansion
Date: 14th century
1 a : the house or hall of an estate : mansion b : a landed estate [See indented definition below]
2 a : a unit of English rural territorial organization; especially : such a unit in the Middle Ages consisting of an estate under a lord enjoying a variety of rights over land and tenants including the right to hold court b : a tract of land in North America occupied by tenants who pay a fixed rent in money or kind to the proprietor
…
to the manor born : born into circumstances of wealth and privilege
[privilege = the advantage that wealthy and powerful people have over other people in a society]
vassal 
Main Entry: a person in the past who received protection and land from a lord in return for loyalty and service 
1: a person under the protection of a feudal lord to whom he has vowed homage and fealty : a feudal tenant 
2: one in a subservient or subordinate position 
Etymology:  Middle English, from Anglo-French, from Medieval Latin vassallus, from vassus servant, vassal, of Celtic origin; akin to Welsh gwas young man, servant
First Known Use: 14th century
serf
Main Entry: serf 
Pronunciation: \ˈsərf\
Function: noun 
Etymology: French, from Old French, from Latin servus slave
Date: 1611
: a member of a servile feudal class bound to the land and subject to the will of its owner