Card dipping is the insertion of a credit or debit card into a reader in an automated teller machine (ATM) or EMV point of sale (POS) terminal.
Dipping can be contrasted with swiping, the act of sliding a magnetic stripe card quickly through a magnetic stripe reader. When a cardholder swipes their magnetic card at a retailer, the point-of-sale terminal reads the card’s magstripe and sends the acquired data to the card issuer for authorization. As an additional security mechanism, the cardholder may be asked to provide another authentication factor by entering a personal identification number (PIN) or by providing a signature.
With dipping, the card is inserted into the reader chip-side first. The card remains in the reader until the dip reader spits the card out or provides the cardholder with an audible or visual signal that indicates the reader has acquired the information it needs from the card's embedded microchip. Industry pundits may also refer to chip dipping as "chip and dip."
As with magnetic card authorizations, smart chip cardholders may be asked to provide a second authentication factor. In the United States, this is typically a signature authorization but in other parts of the world, the second factor is most often a PIN or biometric payment identification factor such as palm, voice, iris or facial recognition.
CreditCards.com has a video that explains more about EMV smart card dipping.