surcharge

1. An addition of extra charge on the agreed, stated, or baseline price. Sometimes portrayed by a buyer as excessive and rapacious; usually portrayed by a seller as justified and necessary. · Our airline tickets cost twenty dollars more than we expected because we had to pay a fuel surcharge.
2. The part of the price of a subsidized good or service that is not covered by the subsidy and so must be paid by the consumer.
3. An overprint on a stamp that alters (usually raises) the original nominal value of the stamp; used especially in times of hyperinflation.
4. A painting in lighter enamel over a darker one that serves as the ground.
5. A charge that has been omitted from an account as payment of a credit to the charged party
6. A penalty for failure to exercise common prudence and skill in the performance of a fiduciary's duties.

Plural surcharges