Standard Mail
A mail class consisting of mailable matter that is not mailed as First-Class Mail or entered as Periodicals. Standard Mail includes matter formerly classified as third 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 Mail (A); matter formerly classified as fourth-class mail is referred to as Standard Mail (B).