The document issued to a lender under a company's seal acknowledging a debt is called?

The document issued to a lender under a company's seal acknowledging a debt is called a debenture. A debenture is a type of bond that is issued by a company to raise funds from investors. When a company issues a debenture, it is essentially borrowing money from investors and promising to pay back the debt with interest. The debenture is typically secured against the assets of the company, which means that if the company is unable to repay the debt, the investors have a claim on the company's assets. The debenture is issued under the company's seal, which serves as an official acknowledgement of the debt owed to the lender. Therefore, the correct answer to the question is "debenture".