noun Date: 1881 an extra tax or charge, a graduated income tax in addition to the normal income tax imposed on the amount by which one's net income exceeds a specified sum
SURTAX
Meaning of SURTAX in English
Merriam Webster. Explanatory English dictionary Merriam Webster. Толковый словарь английского языка Мерриам-Уэбстер. 2012