Look at https://en.wikipedia.org/wiki/Debit_card#Online_debit_system and I have seen many a discussions revolving around the supposedly more secure chip-and-pin/EVM Debit/Credit cards. Are these the same or are there any differences between them?
They are essentially the same. What that article is discussing is how the transaction runs in near-real-time because of the extra authentication step involving a PIN. The term "Online debit system" has been around since before chip and PIN, but the act of entering a PIN at certain types of locations has been in practice for a while. It was swipe and PIN, now (or on it's way in some places), it's chip and PIN rather than swipe.
Chip and PIN is a way for an online debit system to assume a higher level of security than swipe and PIN as chips are currently more difficult to spoof than a magnetic swipe strip.
"Online Debit" obviously refers to online debit (not credit) transactions. The distinction comes for the merchants, who often pay higher transaction fees to accept debit rather than credit transactions.
"Chip and Pin" refers to transactions where you, the consumer, are physically present, insert your card with embedded chip into the chip reader, and then also enter a PIN number as the added level of security to ensure nobody stole your card.
Hope this helps.