From Longman Business Dictionary
indenturein·den·ture /ɪnˈdentʃə-ər/ noun [countableC]1FINANCE a legal agreement between an organization that borrows money by ISSUING bonds (=making them available), and the lenders, stating the interest, the date they will be repaid etcThe homebuilder said it made the interest payments last June in stock, not cash, as allowed by the indentures for the debt.
2LAWa legal agreement, especially one in former times between an employer and an APPRENTICE (=a young person who receives training from an employer to do a particular job), stating the terms of the worker’s employment