An overdraft indicates your account balance is negative; the bank covered the excess. I accidentally caused a negative balance; now I have an overdraft to settle.
Pro Tip 2/3
Additional Fees
Banks often charge fees for overdrafts, which can increase the amount you owe. Due to my overdraft, the bank added a $35 fee to my account.
Pro Tip 3/3
Accidental Overdraft
Sometimes overdrafts happen by accident, if you're unaware of your account balance. I bought coffee and accidentally went into overdraft because I thought I had more money.