PIN try counter
The counter on a card's chip that locks offline PIN after too many wrong attempts, usually three.
The issuer sets the limit when the card is personalised, and the chip counts down on every miss. A terminal can read the current value from EMV tag 9F17, and a correct entry resets it to the limit. Once it hits zero the chip refuses to check any more PINs, and the terminal flags the fact in its Terminal Verification Results. Because the counter lives on the card, the block follows it everywhere, regardless of which shop or country the mistakes were made in.
Unblocking needs the issuer to send a signed issuer script to the card during an online transaction, which in practice usually means an ATM. Hence the classic advice to "go to a cash machine and enter the right PIN" after a lockout. It is one of the few security mechanisms in the card world that works exactly the way everyone assumes it does.