Pieces of mail, also known as postal mail, are items sent through the postal system from one person to another. The term 'pieces of mail' is often used to refer to letters, postcards, and packages. The crossword solution for pieces of mail is ARMOR, which is a five-letter word. ARMOR is a protective covering that is used to defend against attack, damage, or injury. It is often used metaphorically to describe protection from emotional or psychological harm.