The term POSTAL MACHINE is composed of three crossword solutions: SORTER (6 letters), DATER (5 letters), and MAILER (6 letters). A sorter is a machine used to sort mail into different categories. A dater is a machine that prints the date on mail. A MAILER is a machine that seals envelopes and packages for mailing. Together, these three machines form a postal machine, which is used to process mail quickly and efficiently.