Credit card scam is a pretty broad ranging term which encompasses theft as well as fraud which are committed by a credit or any other payment mechanism that is similar to it. The definition is pretty straightforward.
If a card is used to obtain goods without the intent to pay for it or to obtain illegal funds from another account, then that is a credit card related scam. Contrary to popular belief, this isn’t something that rarely happens. In fact, it is a crime that’s quite prevalent worldwide.