Open-end credit (also written open-ended credit) is a credit arrangement with no fixed number of payments: the lender sets a limit, and the borrower can borrow, repay and borrow again for as long as the account stays open. Interest is charged only on the amount actually owed. In everyday use it means much the same as revolving credit, where the full explanation sits.
The term is a formal category in US consumer law. The Truth in Lending Act and its Regulation Z set separate disclosure rules for open-end credit, such as a credit card or a home equity line of credit, and for closed-end credit, such as a car loan or an installment plan, which is repaid in a set schedule and then ends. Lenders must show the annual percentage rate on open-end accounts in account-opening disclosures and on periodic statements.