Means same backwards and forwards. Look at dates, they read the same way backwards as they do forwards.
That only works when you write the date in the WRONG format. The internationally accepted norm is YY/MM/DD, as stated in ISO. (flame suit on )
I guess if you’re gonna talk all fucked up like “On 11th September, 2001, a thing happened”, we’ll gladly disregard your “international standard” and not sound like a buncha poseur dorkos.