Card present and card not present
A card-present sale happens with the card or phone physically at the terminal. A card-not-present sale is online or over the phone. The distinction runs through everything behind the scenes: card-present transactions usually cost less to process and carry stronger protection for the merchant, because the card and often the cardholder were verified at the point of sale. Online, that protection has to come from authentication instead.
In practice
A card-present sale happens with the card or phone at the terminal. A card-not-present sale is online or over the phone. The distinction runs through everything behind the scenes: card-present transactions usually cost less to process and carry stronger protection for the merchant, because the card and often the cardholder were verified at the point of sale.
Online, that protection has to come from somewhere else — which is what Strong Customer Authentication and 3-D Secure are for, and why a properly authenticated online payment shifts most fraud liability away from you.
The practical consequence for a shop running both a till and a website is that the two have different fee profiles and different dispute risk, and a quoted rate that covers only one of them is not comparable to one that covers both.
Also called: CNP, card not present.