[moooo99]

The 3DS is a handheld console by Nintendo.

Just kidding, 3DS is short for 3D-Secure and is an approach to make payments with credit cards more secure. Things like 3DS are mandated by the PSD2 which came into effect a while ago.

PSD(2) is short for payment services directive, its a set of rules to make online payments more secure and reduce the risk of fraud. It has some requirements, such as two factor authentication (3DS) etc for basically any service that is processing payments online.