Payment cards. For questions about storing credit card numbers, see also pci-dss. For questions involving the physical object, see also smartcard (if the card has a chip).
This tag is about credit cards and other payment cards.
If you're storing credit card numbers, then you may be required to comply with the Payment Card Industry Data Security Standard (PCI DSS). See the tag pci-dss.
More and more credit cards contain a chip, which makes them a smart card. See the tag smartcard.