letter of credit

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A letter issued by a bank authorizing the bearer to draw a stated amount of money from the issuing bank, its branches, or other associated banks or agencies.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun finance, banking A document, used primarily in trade finance and issued generally by a financial institution, in which the institution promises to pay debts up to a certain limit to be acquired by the beneficiary against delivery of documents specified in the letter.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a document issued by a bank that guarantees the payment of a customer's draft; substitutes the bank's credit for the customer's credit