http://en.wikipedia.org/wiki/Overdraft#Overdraft_protection_in_the_UK This link describes overdrafts and overdraft protection as they usually work in the US and the UK. "Overdraft protection" means that the bank will honour cheques, debit card payments and/ or cash withdrawals even when you do not have enough money in your current account to pay for them. This protection can also apply if you have exceeded the limit of an agreed overdraft. The precise terms of "overdraft protection" will vary between banks and also some customers may get better terms from others who use the same bank. If you need us to explain this more, please ask. By the way, I have often seen the expression "checking account" on foreign ATMs but have never seen or hear the expression used in the UK. We say "current account". Perhaps others could say if "checking account" is used elsewhere.