Q. When I get my restaurant bill and I see a “service charge”, does that mean the tip? Or am I supposed to tip even on top of that?
As a customer, you can generally assume that a service charge means the tip has already been added to the cost of the meal, and you should only add a further tip if you really want to reward the waiter/waitress.
The exception might be if you have hosted a large party of some sort in which the service charge could mean a room charge. In that case you MAY want to offer an additional tip.
However, be aware that from the point of view of the restaurant / employee, a service charge is not always guaranteed to go to the wait staff in the way that a gratuity would. If the word gratuity is used, the money goes to the employees, but if you don’t see “gratuity” then it is not guaranteed that the service charge is going to the waiter / waitress.
If you feel unsure, just ASK! Do not be shy about asking the wait person what a service charge means, and whether he/she is getting tipped from the service charge. In a tipping society, there is no shame in being upfront about tipping — everyone knows it is happening; your waiter/waitress will be happy to know that you plan on tipping and want to do it right!