"Open end credit" accounts are defined in TILA Regulation Z. IMO, it could only fall under that in an overdraft situation, if the terms met the conditions in TILA. So, a normal bank account would not be an open account.
UCC chapter 4 deals with deposits. I saw a term "deposit contract", but was unable to find a definition. I would look at Florida's version of UCC. Also, look at the paperwork from the account opening to see if the terms and conditions have all the elements needed for a contract.
I also came upon this definition, but not sure if it applies to all accounts in all states:
Signature Card - A contractual form, executed by an account holder, establishing account ownership and setting forth some of the basic terms of the account and provisions of the deposit contract. Banking Definitions