›(UKmailshot)a paper advertisement sent to homes or businesses: An election mailer reached three million homes. The direct mailer we produced was sent out to 250 members. → See alsomailing
›a company, person, or software program that sends lots of letters or messages, especially many copies of the same thing: bulk/junk/mass mailerThe junk mailer was fined for sending billions of messages without permission from the recipients.
›USa special envelope or container for sending things that can easily break, have an unusual shape, or are very small: Robert copied the files onto a disk, put a label on it, and put it in a mailer. → Comparepostal packet