Carding refers to a situation in which numerous payment authorization attempts are used to verify credit card numbers. Dumpsccshop, dumpscvvshop, cheapcvv and other carders get them in bulk.
Carding happens when carders run hundreds or even thousands of small purchases by using various credit cards, then resell valid cards on the dark web.
In a typical carding process, lists of card data are tested against payment processes. This is necessary because carders don't know the quality of obtained cards and they need to identify active ones. These cards can be acquired from a forum or a marketplace.