TD Bank gives you a variety of choices for overdraft protection when you open a new checking account.
An overdraft happens when you don't have enough money in your available balance to cover a transaction (e.g., you buy something for $50 but only have $30 in your account).
If you overdraw your account by less than $5, the bank won't charge an overdraft fee. Beyond that, TD offers a Standard Overdraft Protection service, the Debit Card Advance protection, and a Savings Overdraft Protection plan.
For more information on overdraft protection, check out their offerings.