What is the difference between offline payments and online payments?

Question

Payment systems

Is there a specific classification of offline and online payments? Which payments can definitely be considered offline, and which online? When I was looking for an answer to this question on the Internet, I saw many different wordings and differences between online payments and offline payments, but they are all completely different and sometimes contradict each other.
For example, can a payment by a bank card through a POS terminal through nfc, say, through Paypass, be considered an online payment? From our side, Internet access is not required, we do not produce it, we come directly to the store itself and make a purchase with real contact, but for me, when paying, there is a connection between banks, reservation of funds and confirmation of payment, that is, payment from this point view is obtained online.
Is it possible to call a payment, in which the buyer does not need access to the Internet, offline? Or is it possible to call offline the payment that occurs during a real meeting with the seller? Or is that payment called offline when there is no instant connection between banks, that is, when there is no instant withdrawal of funds and confirmation of the purchase (when the terminal does not immediately contact the issuer's bank)?
I would like to have a clear understanding of the difference between these concepts, if any.
Sorry if I made any mistakes due to ignorance of the procedure for conducting banking operations or technologies.