an additional charge (as for items previously omitted or as a penalty for failure to exercise common caution or common skill)
"The airline added a $50 surcharge to my ticket because I failed to arrive at the airport two hours before departure."
An addition of extra charge on the agreed or stated price.
"The airline added a hefty surcharge to my ticket because I wanted to check in an oversized bag."
charge an extra fee, as for a special service
"The airline added a surcharge to my ticket because I wanted to select my own seat at check-in."
print a new denomination on a stamp or a banknote
"The post office surcharged the old stamps to make them valid for higher postage rates without issuing new ones."
show an omission in (an account) for which credit ought to have been given
"The accountant noticed a surcharge on my invoice because they had failed to apply the discount I was owed."
To apply a surcharge.
"The hotel added an extra fee to our bill for including pets in our room."