sur ‧ tax /ˈsɜːtæks $ ˈsɜːr-/ BrE AmE noun [uncountable]
[ Date: 1800-1900 ; Language: French ; Origin: surtaxe , from sur- ( ⇨ ↑ surcharge ) + taxe 'tax' ]
an additional tax on money you earn if it is higher than a particular amount
sur ‧ tax /ˈsɜːtæks $ ˈsɜːr-/ BrE AmE noun [uncountable]
[ Date: 1800-1900 ; Language: French ; Origin: surtaxe , from sur- ( ⇨ ↑ surcharge ) + taxe 'tax' ]
an additional tax on money you earn if it is higher than a particular amount
Longman Dictionary of Contemporary English. Longman - Словарь современного английского языка. 2012