indorse

from The Century Dictionary.

• noun In heraldry, a bearing like the pale, but of one fourth its width.
• To place something on the back of; burden; load.
• To write one's name, or some brief remark, statement, or memorandum, on the back of (a paper or document), as in assigning, or guaranteeing the payment of, a note or bill of exchange, or in briefing or docketing legal papers, invoices, etc.: as, the bill was indorsed to the bank; he was looking for a friend to indorse his note; a letter indorsed “London, 1868”: loosely used of writing added upon any part of a document.
• To sanction; ratify; approve: as, to indorse a statement or the opinions of another.
• In heraldry, to place back to back.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb obsolete To cover the back of; to load or burden.
• transitive verb To write upon the back or outside of a paper or letter, as a direction, heading, memorandum, or address.
• transitive verb (Law & Com.) To write one's name, alone or with other words, upon the back of (a paper), for the purpose of transferring it, or to secure the payment of a note, draft, or the like; to guarantee the payment, fulfillment, performance, or validity of, or to certify something upon the back of (a check, draft, writ, warrant of arrest, etc.).
• transitive verb To give one's name or support to; to sanction; to aid by approval; to approve.
• transitive verb to write one's name on the back of a note or bill, leaving a blank to be filled by the holder.

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

• verb UK, India, rare Alternative form of endorse.

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

• verb give support or one's approval to
• verb sign as evidence of legal transfer
• verb guarantee as meeting a certain standard
• verb be behind; approve of