1) Impersonal mail 2) Mimeographed item 3) Standard response of a kind 
Used in word processing to describe a repetitive letter in which the names and addresses of individuals are automatically generated from a database or typed individually. 
An individualised document produced by mail merging.
[n] - a letter that is printed in multiple copies and mailed to a list of recipients
noun a letter that is printed in multiple copies and mailed to a list of recipients
a standardized letter that can be sent to any number of persons, occasionally personalized by inserting the name of each recipient in the salutation.