When you get your new credit or prepaid card, you'll need to 'activate' it before you can use it. This is simply a measure to show you received the card safely.
A person you ask your card provider to issue a card to, or to provide cheques to, for them to use on the same account.
APR stands for Annual Percentage Rate. If you have a credit card, the APR is the cost of using your card to borrow money over a 12 month period. Card providers can change the APR at any time, however they’re obliged to notify you when they do.
'In arrears' is the phrase that's used if you've missed a repayment on your credit card.
ATM stands for Automatic Telling Machine, also known as a cash machine or cashpoint.