vas ‧ sal /ˈvæs ə l/ BrE AmE noun [countable]
[ Date: 1300-1400 ; Language: Old French ; Origin: Medieval Latin vassallus , from vassus 'servant' ]
1 . a man in the Middle Ages who was given land to live on by a lord in return for promising to work or fight for him
2 . formal a country that is controlled by another country:
a vassal state