from Investopedia. com
What Does Skimming Mean?
An electronic method of capturing a victim's personal information used by identity thieves. The skimmer is a small device that scans a credit card and stores the information contained in the magnetic strip. Skimming can take place during a legitimate transaction at a business.
Investopedia explains Skimming
Skimming can occur easily in a restaurant because your card is taken away when the bill is being settled. If your server is a skimming identity thief, he or she will, before giving the card back to you, scan the credit card with a hand-held electronic device, which takes only seconds. The electronically captured information is then used to by the thief or sold to other criminals.