Definitions for "STANDARD MAIL"
The U.S. Postal Service's Standard Mail category includes Standard A and Standard B. Standard A is the subclass generally used by large-volume direct mailers, although some magazine circulation promotions are sent by First Class. Standard B is the rates and classifications subcategory used for books and parcels.
bulk-rate mail previously known as Third Class Mail.
A class of mail consisting of mailable matter that is not mailed as first-class mail or entered as periodicals. Standard Mail includes matter formerly classified as third-class and fourth-class mail. Though combined in Standard Mail, matter from each former class remains subject to separate and specific classification eligibility and preparation standards. Matter formerly classified as third-class mail is referred to as Standard A Mail; matter formerly classified as fourth-class mail is referred to as Standard B Mail. (USPS)