Amex distinguishes between two different things here: A “card identification number” (CIC) with four digits and printed on the front of the card (next to the card number); and a “card security code” (CSC) with three digits and on the back of the card. So in essence, it has two different equivalents to the CVV of other card brands (though the CSC is, in lengthz and location, more similar to the CVV of other cards), and online stores can ask for either of them. Of course, nobody memorises what CIC and CSC mean, so such online tools will typically ask just for the three numbers on the back, or the four numbers on the front.