from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A usually impersonal letter in a standardized format that may be sent to different people or to large numbers of recipients.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A letter that is written generically with blanks to be filled in with individual details, often sent in bulk, and frequently regarded as impersonal.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a letter that is printed in multiple copies and mailed to a list of recipients
From form + letter (Wiktionary)